Introduction to IS-IS NANOG 20, Washington DC October 22 -24 Abe Martey amartey@cisco. com Presentation_ID © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 1
Topics 1. IS-IS Overview 2. IS-IS Protocol Concepts 3. CLNP Addressing 4. IS-IS Database 5. MPLS TE Extensions for IS-IS 6. ISP Network Design Considerations 7. Configuration Examples 8. Basic Troubleshooting 9. Further Reading © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 2
1. IS-IS Overview Terminology and Acronyms Intermediate system (IS)- Router Designated Intermediate System (DIS) - Designated Router Pseudonode - Broadcast link emulated as virtual node by DIS End System (ES) - Network Host or workstation Network Service Access Point (NSAP) - Network Layer Address Subnetwork Point of attachment (SNPA) - Datalink interface Packet data Unit (PDU) - Analogous to IP Packet Link State PDU (LSP) - Routing information packet © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 3
IS-IS Overview • The Intermediate Systems to Intermediate System Routing Protocol (IS-IS) was originally designed to route the ISO Connectionless Network Protocol (CLNP). (ISO 10589 or RFC 1142) • Adapted for routing IP in addition to CLNP (RFC 1195) as Integrated or Dual IS-IS • IS-IS is a Link State Protocol similar to the Open Shortest Path First (OSPF). OSPF supports only IP © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 4
IS-IS Overview • IS-IS is an Interior Gateway Protocol (IGP) - for Intra-domain (AS) routing • BGP provides inter-domain routing for IP networks • ISO-IGRP is a Cisco proprietary routing protocol that can be used between CLNP domains © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 5
IS-IS Overview • 3 network layer protocols play together to deliver the ISO defined Connectionless Network Service - CLNP - IS-IS - ES- IS - End System to Intermediate System Protocol • All 3 protocols independently go over layer 2 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 6
IS-IS Overview • CLNP is the ISO equivalent of IP for datagram delivery services (ISO 8473, RFC 994) • ES-IS is designed for routing between network hosts and routers (ISO 9542, RFC 995). • IS-IS for layer 3 routing between routers. (ISO 10589/RFC 1142). Integrated IS-IS (RFC 1195) works within the ISO CNLS framework even when used for routing only IP. © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 7
IS-IS Overview • End System Hellos (ESH) from Hosts and Intermediate System Hellos (ISH) from Routers used for ES-IS neighbor discovery • Intermediate System to Intermediate Systems Hellos (IIH) are used for establishing IS-IS layer 3 adjacencies • ES-IS is somehow tied into IS-IS layer 3 adjacency discovery. ES-IS enabled automatically when IS-IS is configured on Ciscos © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 8
2. IS-IS Protocol Concepts • Nodes • Links • Areas and Adjacencies • Level-1 and level-2 routing © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 9
IS-IS Protocol Concepts Network Nodes • Hosts • Level-1 Routers • Level-2 Routers • Level-1 and Level-2 Pseudonodes on broadcast links only © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 10
IS-IS Protocol Concepts Network Nodes DIS PSN • Broadcast link represented as virtual node, referred to as Pseudonode (PSN) • PSN role played by the Designated Router (DIS) • DIS election is preemptive, based on interface priority with highest MAC address being tie breaker • IS-IS has only one DIS/PSN functionality supports database synchronization between routers on a broadcast type link © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 11
IS-IS Protocol Concepts Network/Link Types • Point-to-Point Links (Po. S, ptp FR, ptp ATM) • Broadcast Links (Multi-point/multi-access, ie Ethernet, mpt FR, mpt ATM or Cisco DPT) • Non-broadcast multi-access treated as broadcast or point-to-point by configuration © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 12
IS-IS Protocol Concepts Area 49. 001 Level-1 Area L 1 L 2 Level-2 Backbone Area 49. 0002 Level-1 Area L 1 © 1999, Cisco Systems, Inc. L 1 L 2 Area 49. 003 L 1 L 2 Level-1 Area L 1 CISCO CONFIDENTIAL - DO NOT DUPLICATE 13
IS-IS Protocol Concepts IS-IS Adjacencies • IIH advertised for detecting neighbor and forming network layer adjacencies • 3 types of IIHs: – Point-to-point – LAN Level-1 – LAN Level-2 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 14
IS-IS Protocol Concepts Point-to Adjacencies Bytes Intra-domain Routing Protocol Discriminator 1 Length Indicator 1 Version/Protocol ID Extension R 1 Pt-to-pt IIH used to establish level-1 or Level-2 pt-to-point adjacency • Only two way communication required on pt-to-pt links by ISO 10589 • 3 -way reliable process recently proposed for standardization in the IETF. Introduces pt-to-pt adjacency state TLV (Type 240) 1 ID Length • R R PDU Type 1 Version 1 Reserved 1 Maximum Area Addresses 1 Reserved (6 bits) Circuit Type Source ID 1 ID Length Holding Time 2 PDU Length 2 Local Circuit ID 1 TLV Fields © 1999, Cisco Systems, Inc. Variable Length CISCO CONFIDENTIAL - DO NOT DUPLICATE 15
IS-IS Protocol Concepts LAN (Broadcast link) Adjacencies bytes Intradomain Routing Protocol Descr. Lenth Indicator 1 Version/Protocol ID Extension 1 ID Length R 1 1 R R PDU Type Reserved 1 1 1 Maximum Area Addresses 1 Reserved/Circuit type 1 Version Source ID Priority ID Length 2 2 1 Lan ID ID Length + 1 Holding Time PDU Length R Holding Time = Hello Interval x Hello Multiplier Priority - Interface Priority for DIS arbitration LAN ID - System ID of DIS + PSN number TYPE LENGTH FIELDS • LAN Level-1 and LAN Level-2 IIH multicast independently to All. L 1 ISs (01 -80 -C 2 -00 -00 -14) and All. L 2 ISs (0180 -C 2 -00 -00 -14) • 3 -way reliable adjacency formation can be enforced due to IS neighbors TLV (Type 2) appended to LAN IIHs Variable © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 16
IS-IS Protocol Concepts Hierarchical Routing Backbone Area 49. 0002 Area 49. 001 Level-1 Routing Level-2 Routing • IS-IS supports 2 -level routing hierarchy • Routing domain is carved into areas. Routing in an area is level-1. Routing between areas is level-2 • All ISO 10589/RFC 1195 areas are stubs © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 17
IS-IS Protocol Concepts IS-IS Packet Types • IS-IS Hello Packets (IIH) Level 1 LAN IS-IS Hello Level 2 LAN IS-IS Hello Point-to-point Hello • Link State Packets (LSP) Level 1 and Level 2 • Complete Sequence Number packets (CSNP) Level 1 and Level 2 • Partial Sequence Number Packets (PSNP) Level 1 and Level 2 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 18
3. CLNS Addressing • NSAP Format • AFI Values • Requirements and Caveats • Examples • Globally unique NSAPs © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 19
CLNS Addressing NSAP Format Area ID AFI Variable length Area address 1 byte 1 - 12 bytes Sys ID NSEL System ID NSEL 6 bytes 1 byte • NSAP format has 3 main components – Area ID – System ID – N-Selector (NSEL) - value is 0 x 00 on a router • NSAP of a router is also called a NET © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 20
CLNS Addressing AFI Values Address Domain AFI Value X. 121 ISO DCC ISO 6523 Local 37 39 47 49 • X. 121 - Int’l plan for public data networks • ISO DCC - Data country code • IS 0 6523 ICD - Telex • Local - For local use within network domain only © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 21
CLNS Addressing Requirements and Caveats • At least one NSAP is required per node • All routers in the same area must have a common Area ID • Each node in an area must have a unique System ID • All level 2 routers in a domain must have unique System IDs relative to each other • All systems belonging to a given domain must have System IDs of the same length in their NSAP addresses © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 22
CLNS Addressing Requirements and Caveats • Multiple NSAPs allowed on Cisco routers for merging, splitting or renumbering • All NSAPs on the same router must have the same system ID. • The maximum size of an NSAP is 20 bytes • Minimum of 8 bytes allowed on Ciscos. 1 byte for area, 6 bytes for system ID and 1 byte for N-selector. AFI prefix recommended to make minimum of 9 bytes © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 23
CLNS Addressing NSAP Examples Example 1 47. 0001. aaaa. bbbb. cccc. 00 Area = 47. 0001, Sys. ID = aaaa. bbbb. cccc, NSel = 00 Example 2 39. 0 f 01. 0002. 0000. 0 c 00. 1111. 00 Area = 39. 0 f 01. 0002, Sys. ID = 0000. 0 c 00. 1111, NSel = 00 Example 3. 49. 0002. 0000. 0007. 00 Area = 49. 0002, Sys. ID = 0000. 0007, Nsel = 00 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 24
CLNS Addressing How do most ISP define System IDs? Router A# Interface Loopback 0 IP address 192. 168. 3. 25 Router isis Net 49. 0001. 1921. 6800. 3025. 00 IP Address conversion process: 192. 168. 3. 25 -> 192. 168. 003. 025 | V 1921. 6800. 3025 | V 49. 001. 1921. 6800. 3025. 00 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 25
CLNS Addressing Globally Unique NSAPs • AFI 47 (ISO 6523 ICD) is allocated via national sponsoring authority of the International Registration Authority (RA), usually a national standards body NIST - allocated IDI 0005 and 0006 BSI subsidiary IOTA allocated 0124 for assignment of ATM End Systems Addresses • AFI 39 also administered through national institutions IDI 0840 allocated to ANSI NIST - United States National Institute of Standards BSI - British Standards Institute IOTA -Identifiers for Organizations for Telecommunications Addressing © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 26
CLNS Addressing Globally Unique NSAPs 47 0124 XXXXX YYYYYYY AABBCCDDEEFF 00 AFI IDI ORG ID ORG ASSIGNED SYS ID NSEL Globally unique NSAPs make sense for interconnected telecommunications systems such as ATM switches, SONET/SDH ADMs that use CLNS based applications for management. For ISP networks, the local AFI (49) would just be fine! Why? © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 27
4. IS-IS Link State Database • Link State Packets • Sequence Number Packets • More on IS- IS Metrics • Flooding • Database Parameters, Flags and Timers • SPF Algorithm © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 28
IS-IS LS Database Link State Packets LSP: RTB. 00 -00 LSP: RTC. 00 -00 RTC RTB. RTA LSP: RTA. 00 -00 RTD. LSP: RTD. 00 -00 © 1999, Cisco Systems, Inc. RTE LSP: RTE. 00 -00 CISCO CONFIDENTIAL - DO NOT DUPLICATE 29
IS-IS LS Database IS-IS Packet Format IS-IS Packets are made of the following: • A Fixed Header Contains generic packet information and other specific information about the packet • Type, Length, Value (TLV) Fields TLVs are blocks of specific routing-related information in IS-IS packets © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 30
IS-IS LS Database Generic Packet Format No. of Octets Intra-domain Routing Protocol Discriminator 1 Length Indicator 1 Version/Protocol ID Extension ID Length R 1 1 R R PDU Type 1 Version 1 Reserved 1 Maximum Area Addresses 1 Packet-Specific Header Fields TLV Fields © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 31
IS-IS LS Database LSP Format Octets Intradomain Routing Proto Descriminator 1 Lenth Indicator 1 Version/Protocol ID Extension 1 1 ID Length Reserved 1 PDU Length R 1 1 1 Maximum Area Addresses R 2 R PDU Type Version 2 ID Length + 2 4 2 Remaining Lifetime LSP ID Sequence Number Checksum P ATT LSPDBOL IS Type TYPE LENGTH VALUE FIELDS © 1999, Cisco Systems, Inc. 1 Variable CISCO CONFIDENTIAL - DO NOT DUPLICATE 32
IS-IS LS Database LS Packet Identifier (LSPID) 00 c 0. 0040. abcd. 02 -01 Sys ID PSN ID LSP No. • Sys ID - System ID of IS or DIS in case of PSN LSP. • PSN ID - Zero for Non-PSN LSP and Non-zero for PSN LSP • LSP Number - Fragmentation number © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 33
Complete Sequence Number Packets (CSNPs) • Describes all known LSPs in the LS Database • Standard IS-IS packet format Fixed Header and TLV Fields • Each TLV includes the following info about each known LSP: LSP ID Remaining Lifetime Sequence number Checksum © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 34
Partial Sequence Number Packets (PSNPs) • PSNPs are similarly constructed as CSNPs but have summaries of only specific LSPs • PSNPs are used in 2 ways: – To acknowledge receipt of LSP on pt-to-pt links – To request transmission of the latest version of an LSP © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 35
Level-1 TLVs TLV Name Area Address Type Origin 1 2 ISO 10589 End System Neighbors 3 ISO 10589 Authentication information 10 ISO 10589 IP Internal Reachability Information 128 RFC 1195 Protocols Supported 129 RFC 1195 IP Interface Address 132 RFC 1195 Intermediate System Neighbors © 1999, Cisco Systems, Inc. ISO 10589 CISCO CONFIDENTIAL - DO NOT DUPLICATE 36
Level-2 TLVs TLV Name Area Address Type Origin 1 2 ISO 10589 4 5 ISO 10589 10 ISO 10589 IP Internal Reachability Information 128 RFC 1195 Protocols Supported 129 RFC 1195 IP External Reachability Information 130 RFC 1195 Inter-domain Routing Protocol Information 131 RFC 1195 IP Interface Address 132 RFC 1195 Intermediate System Neighbors Partition Designated Level-2 IS Prefix Neighbors Authentication information © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 37
New TLVs TLV Name Extended IS Reachability Information Type 22 Comments TE Extension. Replaces TLV 2 Router-Id 134 TE Extension Extended IP Reachability Information 135 TE extension used in place of TLV 128 or 130 Dynamic Hostname Information 137 For dynamic distribution of Hostname to NET mapping via LSP Flooding Point-to-Point Adjacency State 240 © 1999, Cisco Systems, Inc. Reliable Pt-to-pt adjacency formation CISCO CONFIDENTIAL - DO NOT DUPLICATE 38
Old IS-IS Metrics • ISO 10589 specifies 4 metric types Default - Supported by all routers. Delay - measures transit delay Expense - Measures the monetary cost of link utilization Error - measures error probability • Default metric type must be supported by all implementations • Other metric types specified for Qo. S routing. Not supported in Cisco IOS and most other vendor implementations © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 39
Old IS-IS Metrics • Metric Information is carried in the following TLVs: ©IS Neighbors ©ES Neighbors ©Prefix Neighbors ©IP Internal Reachability ©IP External Reachability ©Extended IP Reachability ©Extended IS Reachability © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 40
Old IS-IS Metrics Byte(s) 0 S I/E S S Default Metric (6 bits) 1 1 I/E Delay Metric Expense Metric I/E Error Metric 1 1 IP Address 4 Subnet Mask 4 • Maximum metric per interface is 63 • Maximum path metric is 1023 • There is no automatic assignment based on interface bandwidth • Cisco uses default of 10 on all interfaces regardless of bandwidth © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 41
Flooding and LSDB synchronization • Acknowledgement-based reliable mechanism on pt-to-point links • Flooding on broadcast links depends on periodic advertisements of CSNPs for reliable flooding and synchronization © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 42
SRM and SSN Flags. • Send Routing Message flag (SRMflag) and Sequence Number flag (SSNflag) are used by the Update Process to control delivery and acknowledgement of LSPs SRMFlag - If set for a LSP on a specific link, indicates the LSP should be flooded on that link SSNFlag - If set for a LSP on a link, means send a PSNP over that link to acknowledge receipt of LSP © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 43
Flooding on Pt-to-pt links RTA RTB RTC Interface 1 Interface 4 Interface 2 LSP RTA. 00 -00 SEQ#100 PSNP RTA. 00 -00 SEQ#100 © 1999, Cisco Systems, Inc. Interface 3 LSP RTA. 00 -00 SEQ#100 PSNP RTA. 00 -00 SEQ#100 CISCO CONFIDENTIAL - DO NOT DUPLICATE 44
Flooding on Broadcast Links RTX RTA (DIS) RTB RTC RTX LSP RTX. 00 -00 SEQ#1 PSNP RTX. 00 -00 RTA SEQ#1 RTA LSP RTX. 00 -00 SEQ#1 CSNP RTA. 00 RTB. 00 RTC. 00 RTX. 00 RTA © 1999, Cisco Systems, Inc. X LSP RTX. 00 -00 SEQ#1 PSNP RTX. 00 -00 SEQ#1 RTB PSNP RTX. 00 -00 SEQ#1 RTC CISCO CONFIDENTIAL - DO NOT DUPLICATE 45
IS-IS Database Timers Timer Maxage LSP Refresh Interval LSP Transmission Interval Default Value Cisco IOS Command 1200 s isis max-lsp-interval isis refresh-interval 900 s 33 ms isis lsp-interval LSP Retransmit Interval 5 s isis retransmit-interval CSNP Interval 10 s isis csnp-interval © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 46
SPF Algorithm • Shortest Path First Algorithm (SPF), also known as Dijkstra (named after Dutch Mathematician) is used by link state protocols to obtain best paths through network • Works by building shortest path tree from calculating router (root) to all destinations in the network • SPF Process runs over level-1 and level-2 databases separately © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 47
SPF Algorithm • In default mode, SPF process runs no frequent than every 5 s • Full SPF is run when topology changes • When leaf elements such as IP prefixes change, routing table is adjusted with Partial Route Calculation (PRC) • PRC evaluates only routes that changed hence less CPU intensive and relatively fast © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 48
SPF Algorithm • Duration of SPF depends on many factors such as: Number of nodes Number of links Number of IP prefixes Degree of mesh (especially for NBMA) Speed of Route Processor © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 49
5. IS-IS Extensions for MPLS TE • Wide Metrics • Extended IS Reachability Information • Extended IP Reachability Information • Sub TLVs © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 50
IS-IS Extensions for MPLS TE Wide Metric TLV Name Type Extended IS Reachability Information 22 Extended IP Reachability Information 135 Comments TE Extension to replace TLV 2 TE extension to IS-IS, used in place of TLV 128 or 130 • Traffic engineering extensions to IS-IS introduces reuse fields for non-implemented Qo. S metrics for larger Default metric values in TLV 22 and TLV 135 • 3 byte metric field in TLV 22 • 4 byte metric field in TLV 135 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 51
IS-IS Extensions for MPLS TE TLVs 22 • Type (1 byte): 22 • Length (1 byte): Total Length of Value Field • Value: 3 bytes default metric information 7 bytes of system ID + pseudonode number 1 byte of length of sub-TLVs 0 -244 bytes of sub-TLVs © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 52
IS-IS Extensions for MPLS TE TLVs 135 • Type (1 byte): 135 • Length (1 byte): Total Length of Value Field • Value: 4 bytes default metric information 1 byte of control information 1 bit up/down status 1 bit sub-TLV presence indication 6 bits prefix length 0 -4 bytes of IPV 4 Prefix 0 -250 bytes of optional sub-TLVs 1 byte to specify length of sub-TLVs 0 -249 bytes of sub-TLVs © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 53
IS-IS Extensions for MPLS TE Sub-TLVs Sub-TLV Name Type Length (bytes) IPV 4 Interface Address 3 6 4 4 IPV 4 Neighbor Address 8 4 Maximum Link Bandwidth 9 4 Reservable Link Bandwidth Unreserved Link Bandwidth 10 11 4 Administrative Group ( color ) 32 • Sub-TLVs are used to flood MPLS TE resource information and link attributes © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 54
6. ISP Network Design Considerations • Sub-Optimal Level 1 Routing • 2 Layer Domain-wide Prefix distribution • Running IS-IS over NBMA • Routing Convergence © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 55
ISP Network Design Considerations Sub-optimal level-1 routing • IS - IS Areas in 1142 and RFC 1195 are stubs. • No inter-area routes leaked from L-1 -2 • L-1 routers point default to nearest L-1 -2 router based on attach bit set in L-1 LSP by level-1 -2 routers © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 56
ISP Network Design Considerations Sub-optimal level-1 routing Area 49. 001 RTA Backbone Area 49. 0002 RTC 10 OC 12 RTF L 1 L 2 L 1 RTE L 1 L 2 10 RTB L 1 L 2 10 OC 48 RTD • RTA points default towards RTC because it is closer • Nearest L 2 Router may not be best path out © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 57
ISP Network Design Considerations Sub-optimal level-1 routing Area 49. 001 RTA L 2 RTC 10 OC 12 RTE RTF L 2 10 L 2 RTB L 2 10 L 2 OC 48 RTD • Workaround is to put every router into single area and run level-1 or level-2 routing • Make every router level-1 or level-2 only. By default Cisco routers come up as level-1 -2 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 58
ISP Network Design Considerations Domain Wide Prefix Distribution • AKA Route Leaking • Allows L-1 -2 routers to advertise inter-area routes into L 1 • L 1 routers can then determine optimal paths for destinations in other areas • Allows scaling IS-IS networks by building hierarchy into network architecture • draft-ietf-isis-domain-wide-02. txt © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 59
ISP Network Design Considerations Mesh-group RTA RTB RTC RTD RTE • Configure RTA, RTB, RTC, RTD into mesh-group to reduce redundant flooding. RTE on Redundant path • LSPs received from a member of mesh-group will be flooded to only non-members • draft-balya-parker-mesh-00. txt © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 60
ISP Network Design Considerations Routing Convergence • Current networks configured for stability and decent convergence • Optimizing for faster convergence desirable given improved quality of optical links • Risks in case of unexpected instabilities Constant LSP regeneration Extra Flooding Processor intensive SPF runs, etc © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 61
ISP Network Design Considerations Routing Convergence • Challenges with SPF reduced by PRC • Redundant flooding can be alleviated with mesh-groups • Distributed or separate forwarding engines should take load off Route Processors • Above gains have been leveraged to improve routing convergence in some versions of Cisco IOS. • How? By using small hold-downs and short interval between SPF runs and intelligent stabilization algorithms in case of persistent churns • Enhancements in Cisco IOS 12. 1 provide 8 x faster convergence than current 12. 0 S releases for large networks of the order of 1000 s © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 62
7. Configuring IS-IS on Ciscos • Basic Configuration • Multi-point configuration (ATM and FR) • Typical ISP router configuration • Default route • Redistribution and Summarization • MPLS TE Configuration © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 63
Basic Configuration GSR 1 12. 1. 1. 0/24 . 8 GSR 2 . 2 e 0 GSR 4 . 5 198. 168. 1. 4/30 Pos 1/0 hostname GSR 2 clns routing ! interface Loopback 0 ip address 13. 1. 1. 2 255. 0 ip router isis SJ interface Ethernet 0 ip address 12. 1. 1. 2 255. 0 ip router isis SJ ! interface POS 2/0 ip address 10. 1. 1. 1 255. 252 ip router isis SJ ! router isis SJ net 49. 0001. 0000. 0002. 00 ! clns host GSR 1 49. 0001. 0000. 0008. 00 © 1999, Cisco Systems, Inc. . 6 Pos 1/0 hostname GSR 4 clns routing ! interface Loopback 0 ip address 13. 1. 1. 2 255. 0 ip router isis SJ ! interface POS 2/0 ip address 10. 1. 1. 2 255. 0 ip router isis SJ ! router isis SJ net 49. 0002. 0000. 0004. 00 CISCO CONFIDENTIAL - DO NOT DUPLICATE 64
Verifying Operation show clns neighbors GSR 2#show clns neighbors System Id GSR 1 GSR 4 Interface SNPA State Holdtime Type Protocol Et 0 00 d 0. 58 eb. d 601 Up 8 L 1 L 2 IS-IS PO 2/0 *HDLC* Up 25 L 2 IS-IS GSR 2#show clns neighbors detail System Id Interface SNPA State Holdtime Type Protocol GSR 1 Et 0 00 d 0. 58 eb. d 601 Up 9 L 1 L 2 IS-IS Area Address(es): 49. 0001 IP Address(es): 12. 1. 1. 8* Uptime: 00: 08: 57 GSR 4 PO 2/0 *HDLC* Up 24 L 2 IS-IS Area Address(es): 49. 0002 IP Address(es): 10. 1. 1. 2* Uptime: 00: 24: 08 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 65
Verifying operation show clns interface GSR 2#sh clns interface pos 2/0 POS 2/0 is up, line protocol is up Checksums enabled, MTU 4470, Encapsulation HDLC ERPDUs enabled, min. interval 10 msec. RDPDUs enabled, min. interval 100 msec. , Addr Mask enabled Congestion Experienced bit set at 4 packets CLNS fast switching disabled CLNS SSE switching disabled DEC compatibility mode OFF for this interface Next ESH/ISH in 43 seconds Routing Protocol: IS-IS Circuit Type: level-1 -2 Interface number 0 x 0, local circuit ID 0 x 100 Level-1 Metric: 10, Priority: 64, Circuit ID: GSR 4. 00 Number of active level-1 adjacencies: 0 Level-2 Metric: 10, Priority: 64, Circuit ID: GSR 2. 00 Number of active level-2 adjacencies: 1 Next IS-IS Hello in 2 seconds © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 66
Verifying operation show clns interface GSR 2#sh clns interface e 0 Ethernet 0 is up, line protocol is up Checksums enabled, MTU 1497, Encapsulation SAP ERPDUs enabled, min. interval 10 msec. RDPDUs enabled, min. interval 100 msec. , Addr Mask enabled Congestion Experienced bit set at 4 packets CLNS fast switching disabled CLNS SSE switching disabled DEC compatibility mode OFF for this interface Next ESH/ISH in 4 seconds Routing Protocol: IS-IS Circuit Type: level-1 -2 Interface number 0 x 1, local circuit ID 0 x 1 Level-1 Metric: 10, Priority: 64, Circuit ID: GSR 1. 01 Number of active level-1 adjacencies: 1 Level-2 Metric: 10, Priority: 64, Circuit ID: GSR 1. 01 Number of active level-2 adjacencies: 1 Next IS-IS LAN Level-1 Hello in 3 seconds Next IS-IS LAN Level-2 Hello in 5 seconds © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 67
Verifying operation show clns protocol GSR 2#sh clns protocol IS-IS Router: SJ System Id: 0000. 0002. 00 IS-Type: level-1 -2 Manual area address(es): 49. 0001 Routing for area address(es): 49. 0001 Interfaces supported by IS-IS: Loopback 0 - IP Ethernet 0 - IP POS 2/0 - IP Redistributing: static Distance: 110 RRR level: none Generate narrow metrics: level-1 -2 Accept narrow metrics: level-1 -2 Generate wide metrics: none Accept wide metrics: none © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 68
Verifying Operation show isis topology GSR 2#sh isis topology IS-IS paths to level-1 routers System Id Metric Next-Hop GSR 2 -GSR 1 10 GSR 1 IS-IS paths to level-2 routers System Id Metric Next-Hop GSR 2 -GSR 4 10 GSR 4 GSR 1 10 GSR 1 © 1999, Cisco Systems, Inc. Interface SNPA Et 0 00 d 0. 58 eb. d 601 Interface SNPA PO 2/0 Et 0 *HDLC* 00 d 0. 58 eb. d 601 CISCO CONFIDENTIAL - DO NOT DUPLICATE 69
Verifying Operation show isis database level-n detail <lspid> GSR 2#show isis database level-1 detail GSR 2. 00 -00 IS-IS Level-1 LSP GSR 2. 00 -00 LSPID LSP Seq Num LSP Checksum LSP Holdtime GSR 2. 00 -00 * 0 x 0000000 E 0 x. DAE 4 1197 Area Address: 49. 0001 NLPID: 0 x. CC Hostname: GSR 2 IP Address: 13. 1. 1. 2 Metric: 10 IP 12. 1. 1. 0 255. 0 Metric: 10 IP 10. 1. 1. 0 255. 252 Metric: 10 IP 13. 1. 1. 2 255 Metric: 10 IS GSR 2. 02 Metric: 10 IS GSR 1. 01 Metric: 0 ES GSR 2 © 1999, Cisco Systems, Inc. ATT/P/OL 1/0/0 CISCO CONFIDENTIAL - DO NOT DUPLICATE 70
Verifying Operation show isis database level-n detail <lspid> GSR 2#show isis database level-2 detail GSR 2. 00 -00 IS-IS Level-2 LSP GSR 2. 00 -00 LSPID LSP Seq Num LSP Checksum LSP Holdtime GSR 2. 00 -00 * 0 x 0000000 E 0 x 08 B 5 986 Area Address: 49. 0001 NLPID: 0 x. CC Hostname: GSR 2 IP Address: 13. 1. 1. 2 Metric: 10 IS GSR 2. 02 Metric: 10 IS GSR 1. 01 Metric: 10 IS GSR 4. 00 Metric: 10 IP 10. 1. 1. 0 255. 252 Metric: 10 IP 12. 1. 1. 0 255. 0 Metric: 10 IP 13. 1. 1. 2 255 © 1999, Cisco Systems, Inc. ATT/P/OL 0/0/0 CISCO CONFIDENTIAL - DO NOT DUPLICATE 71
Verifying Operation show isis database level-n detail <lspid> GSR 2#sh isis dat level-1 detail GSR 1. 01 -00 IS-IS Level-1 LSP GSR 1. 01 -00 LSPID LSP Seq Num LSP Checksum LSP Holdtime GSR 1. 01 -00 0 x 00000007 0 x. AF 8 E 616 Metric: 0 IS GSR 1. 00 Metric: 0 IS GSR 2. 00 ATT/P/OL 0/0/0 • Pseudonode LSP (GSR 1. 01 -00) is generated by GSR 1 which is DIS on ethernet 0 of GSR 2 • PSN LSP Lists all known routers connected to LAN © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 72
![Verifying Operation show ip route [isis] GSR 2#sh ip route Codes: C - connected,](https://present5.com/presentation/929868f4beb2e80930a942cc6b8a1ff3/image-73.jpg "Verifying Operation show ip route [isis] GSR 2#sh ip route Codes: C - connected,")
Verifying Operation show ip route [isis] GSR 2#sh ip route Codes: C - connected, S - static, i - IS-IS, L 1 - IS-IS level-1, L 2 - IS-IS level-2, ia - IS-IS inter area 10. 0/30 is subnetted, 1 subnets C 10. 1. 1. 0 is directly connected, POS 2/0 12. 0. 0. 0/24 is subnetted, 1 subnets C 12. 1. 1. 0 is directly connected, Ethernet 0 13. 0. 0. 0/32 is subnetted, 3 subnets i L 1 13. 1. 1. 8 [115/20] via 12. 1. 1. 8, Ethernet 0 i L 2 13. 1. 1. 4 [115/20] via 10. 1. 1. 2, POS 2/0 C 13. 1. 1. 2 is directly connected, Loopback 0 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 73
ATM Multi-pt Configuration GSR 3 . 3 10. 1. 1. 0/24 GSR 4 . 4 hostname GSR 3 ! clns routing hostname GSR 4 ! clns routing ! ! interface ATM 6/0. 1 multipoint ip address 10. 1. 1. 3 255. 0 ip address 10. 1. 1. 4 255. 0 no ip directed-broadcast ip router isis atm pvc 1 0 8 aal 5 snap map-group GSR_Lab ! ! router isis net 49. 0001. 0000. 0003. 00 net 49. 0001. 0000. 0004. 00 is-type level-2 -only ! ! map-list GSR_Lab ip 10. 1. 1. 4 atm-vc 1 broadcast ip 10. 1. 1. 3 atm-vc 1 broadcast clns 49. 0001. 0000. 0004. 00 atm-vc 1 broadcast clns 49. 0001. 0000. 0003. 00 atm-vc 1 broadcast © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 74
ATM Multi-pt Configuration GSR 3#sh clns neighbors System Id GSR 4 Interface SNPA AT 6/0. 1 VC 1 State Holdtime Type Protocol Up 7 L 2 IS-IS GSR 3#show clns int atm 6/0. 1 ATM 6/0. 1 is up, line protocol is up Checksums enabled, MTU 4467, Encapsulation ATM ERPDUs enabled, min. interval 10 msec. RDPDUs enabled, min. interval 100 msec. , Addr Mask enabled Congestion Experienced bit set at 4 packets CLNS fast switching disabled CLNS SSE switching disabled DEC compatibility mode OFF for this interface Next ESH/ISH in 8 seconds Routing Protocol: IS-IS Circuit Type: level-1 -2 Interface number 0 x 0, local circuit ID 0 x 1 Level-2 Metric: 10, Priority: 64, Circuit ID: GSR 4. 01 Number of active level-2 adjacencies: 1 Next IS-IS LAN Level-2 Hello in 7 seconds © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 75
ATM Pt-to-pt Configuration GSR 3 . 3 10. 1. 1. 0/24 hostname GSR 3 ! clns routing ! interface ATM 6/0. 2 point-to-point ip address 192. 168. 1. 1 255. 252 no ip directed-broadcast ip router isis atm pvc 2 0 10 aal 5 snap ! router isis net 49. 0001. 0000. 0003. 00 is-type level-2 -only © 1999, Cisco Systems, Inc. GSR 4 . 4 hostname GSR 4 ! clns routing ! interface ATM 6/0. 2 point-to-point ip address 192. 168. 1. 2 255. 252 no ip directed-broadcast ip router isis atm pvc 2 0 10 aal 5 snap ! router isis net 49. 0001. 0000. 0004. 00 is-type level-2 -only CISCO CONFIDENTIAL - DO NOT DUPLICATE 76
ATM Point-pt Configuration GSR 3#show clns neighbors System Id GSR 4 Interface SNPA AT 6/0. 2 VC 2 AT 6/0. 1 VC 1 State Holdtime Type Protocol Up 26 L 2 IS-IS Up 9 L 2 IS-IS GSR 3#show clns int atm 6/0. 2 ATM 6/0. 2 is up, line protocol is up Checksums enabled, MTU 4467, Encapsulation ATM ERPDUs enabled, min. interval 10 msec. RDPDUs enabled, min. interval 100 msec. , Addr Mask enabled Congestion Experienced bit set at 4 packets CLNS fast switching disabled CLNS SSE switching disabled DEC compatibility mode OFF for this interface Next ESH/ISH in 16 seconds Routing Protocol: IS-IS Circuit Type: level-1 -2 Interface number 0 x 1, local circuit ID 0 x 100 Level-2 Metric: 10, Priority: 64, Circuit ID: GSR 3. 00 Number of active level-2 adjacencies: 1 Next IS-IS Hello in 3 seconds © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 77
Frame Relay Multi-pt Configuration RTA . 1 FR CLOUD . 2 RTB 192. 168. 1. 0/24 hostname RTA ! clns routing ! interface Serial 0 ip address 192. 168. 1. 1 255. 0 ip router isis encapsulation frame-relay map clns 200 broadcast frame-relay map ip 192. 168. 1. 2 200 ! router isis net 49. 0002. 0000. 0001. 00 is-type level-2 -only © 1999, Cisco Systems, Inc. Hostname RTB ! clns routing ! interface Serial 0 ip address 192. 168. 1. 2 255. 0 ip router isis isp encapsulation frame-relay map clns 200 broadcast frame-relay map ip 192. 168. 1. 1 200 ! router isis net 49. 0001. 0000. 0002. 00 is-type level-2 -only CISCO CONFIDENTIAL - DO NOT DUPLICATE 78
Typical ISP Router Configuration GSR 1# interface Loopback 0 ip address 172. 160. 250. 1 255 ! interface POS 1/0 ip address 192. 168. 1. 1 255. 0 isis metric 100 level-2 isis hello-interval 12 level-2 isis hello-multiplier 5 level-2 isis retransmit-interval 100 ! router isis SJ summary-address 172. 160. 0. 0 255. 0. 0 passive-interface Loopback 0 distance 15 ip net 49. 0001. 0000. 0001. 0002. 0001. 1721. 6025. 0001. 00 is-type level-2 -only metric-style wide spf-interval 30 log-adjacency-changes © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 79
default-information originate Used for originating default into level-2 Level-1 routers automatically point default to nearest level-2 router based on attach bit information Hostname RTE ! router isis SJ default-information originate net 49. 0002. 0000. 0002. 00 ! © 1999, Cisco Systems, Inc. RTB#sh isis database RTE. 00 -00 detail level-2 IS-IS Level-2 LSP RTE. 00 -00 LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL RTE. 00 -00 * 0 x 0000008 D 0 x. DBD 0 848 0/0/0 Area Address: 49. 0002 NLPID: 0 x 81 0 x. CC IP Address: 172. 16. 2. 2 Metric: 10 IS RTE. 01 Metric: 10 IS RTB. 00 Metric: 0 IP-External 0. 0 Metric: 20 IP 172. 16. 5. 16 255. 252 Metric: 20 IP 172. 16. 5. 12 255. 252 Metric: 10 IP 172. 16. 5. 4 255. 252 Metric: 10 IP 172. 16. 2. 0 255. 0 CISCO CONFIDENTIAL - DO NOT DUPLICATE 80
Verifying Operation show isis database GSR 2#sh isis database IS-IS Level-1 Link State Database LSPID LSP Seq Num LSP Checksum GSR 2. 00 -00 * 0 x 00000008 0 x 7399 GSR 1. 00 -00 0 x 00000002 0 x 7307 GSR 1. 01 -00 0 x 00000003 0 x. B 78 A LSP Holdtime 716 545 574 ATT/P/OL 1/0/0 0/0/0 IS-IS Level-2 Link State Database LSPID LSP Seq Num LSP Checksum GSR 2. 00 -00 * 0 x 00000009 0 x. C 049 GSR 4. 00 -00 0 x 00000009 0 x 71 D 6 GSR 1. 00 -00 0 x 0000626 A 0 x 1963 GSR 1. 01 -00 0 x 0000696 F 0 x 32 C 2 LSP Holdtime 1054 999 701 906 ATT/P/OL 0/0/0 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 81
Summarization RTB 172. 16. 5. 0/30 172. 170. 1. 0/24. 5 RTE . 6 hostname RTB ! interface Ethernet 0 ip address 172. 170. 1. 1 255. 0 ip router isis SJ ! router isis SJ summary-address 172. 170. 0. 0 255. 0. 0 net 49. 0001. 0000. 0001. 00 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 82
Summarization RTE#sh ip route Gateway of last resort is not set i L 2 172. 170. 0. 0/16 [115/20] via 172. 16. 5. 5, Serial 0 172. 16. 0. 0/16 is subnetted, 1 subnets C 172. 16. 5. 4/30 is directly connected, Serial 0 RTB#sh isis dat RTB. 00 -00 l 2 detail IS-IS Level-2 LSP RTB. 00 -00 LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL RTB. 00 -00 * 0 x 00000096 0 x 86 F 6 877 0/0/0 Area Address: 49. 0001 NLPID: 0 x 81 0 x. CC IP Address: 172. 170. 1. 1 Metric: 10 IS RTB. 02 Metric: 10 IS RTE. 00 Metric: 10 IS RTF. 00 Metric: 10 IP 172. 16. 5. 4 255. 252 Metric: 10 IP 172. 170. 0. 0 255. 0. 0 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 83
Redistribution IS-IS Domain RTB RTE 172. 16. 5. 0/30. 5 172. 170. 1. 0/24 OSPF Domain . 6 . 3 . 4 172. 16. 2. 0/24 RTG 172. 80. 1. 1/24 RTE router ospf 1 network 172. 16. 2. 0 0. 0. 0. 255 area 0 ! router isis SJ redistribute ospf 1 metric 20 metric-type internal level-2 net 49. 0002. 0000. 0002. 00 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 84
Redistribution RTE#sh isis dat rte. 00 -00 level-2 detail IS-IS Level-2 LSP RTE. 00 -00 LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL RTE. 00 -00 * 0 x 000003 B 3 0 x 66 A 7 859 0/0/0 Area Address: 49. 0002 NLPID: 0 x 81 0 x. CC IP Address: 172. 16. 2. 2 Metric: 10 IS RTE. 01 Metric: 10 IS RTB. 00 Metric: 20 IP-External 172. 180. 0. 0 255. 0. 0 Metric: 20 IP 172. 16. 5. 16 255. 252 Metric: 20 IP 172. 16. 5. 12 255. 252 Metric: 10 IP 172. 16. 5. 4 255. 252 Metric: 10 IP 172. 16. 2. 0 255. 0 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 85
MPLS TE Configuration 10. 1. 1. 0/30 Pos 2/0. 1. 9 GSR 1 GSR 4 12. 1. 1. 0/30 GSR 2. 2 Pos 3/0 Pos 2/0 . 4 Eth 0 Pos 4/0 . 8 Eth 0 . 5 Pos 2/2 Pos 4/0 . 10 10. 1. 1. 8/30 10. 1. 1. 4/30 . 6 GSR 6 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 86
MPLS TE Configuration IS-IS configuration hostname GSR 2 ! mpls traffic-eng tunnels interface Loopback 0 ip address 13. 1. 1. 2 255 no ip directed-broadcast ip router isis SJ ! interface POS 2/0 ip address 10. 1. 1. 1 255. 252 ip router isis SJ mpls traffic-eng tunnels isis metric 100 level-2 ip rsvp bandwidth 10000 ! interface POS 3/0 ip address 10. 1. 1. 9 255. 252 ip router isis SJ mpls traffic-eng tunnels isis metric 100 level-2 © 1999, Cisco Systems, Inc. ip rsvp bandwidth 10000 ! router isis SJ net 49. 0001. 0000. 0002. 00 is-type level-2 -only metric-style wide log-adjacency-changes mpls traffic-eng router-id Loopback 0 mpls traffic-eng level-2 ! CISCO CONFIDENTIAL - DO NOT DUPLICATE 87
MPLS TE Configuration Dynamic Path hostname GSR 2 ! interface Tunnel 1 ip unnumbered Loopback 0 no ip directed-broadcast tunnel destination 13. 1. 1. 4 tunnel mode mpls traffic-eng tunnel mpls traffic-eng autoroute announce tunnel mpls traffic-eng bandwidth 10000 tunnel mpls traffic-eng path-option 1 dynamic • Tunnel is configured on head end router • For dynamic path discovery, dynamic path option is used © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 88
MPLS TE Configuration Explicit Path hostname GSR 2 ! interface Tunnel 2 ip unnumbered Loopback 0 no ip directed-broadcast tunnel destination 13. 1. 1. 4 tunnel mode mpls traffic-eng tunnel mpls traffic-eng autoroute announce tunnel mpls traffic-eng path-option 1 explicit name Via. GSR 6 ! ip explicit-path name Via. GSR 6 enable next-address 13. 1. 1. 6 next-address 13. 1. 1. 4 ! ip route 192. 168. 5. 0 255. 0 Tunnel 2 • Tunnel is configured on head end router • Explicit path defined © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 89
MPLS TE Configuration GSR 2#show mpls traffic-eng tunn brief Signalling Summary: LSP Tunnels Process: running RSVP Process: running Forwarding: enabled Periodic reoptimization: every 3600 seconds, next in 1180 seconds TUNNEL NAME DESTINATION STATUS STATE GSR 2_t 1 13. 1. 1. 4 up up GSR 2_t 2 13. 1. 1. 4 up up Displayed 2 (of 2) heads, 0 (of 0) midpoints, 0 (of 0) tails © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 90
MPLS TE Configuration GSR 2#sh mpls traffic-eng tunnels name GSR 2_t 1 Name: GSR 2_t 1 Status: Admin: up Oper: up (Tunnel 1) Destination: 13. 1. 1. 4 Path: valid Signalling: connected path option 1, type dynamic (Basis for Setup, path weight 100) Config Paramters: Bandwidth: 1000 Priority: 7 7 Affinity: 0 x 0/0 x. FFFF Auto. Route: enabled Lock. Down: disabled In. Label : Out. Label : POS 2/0, implicit-null RSVP Signalling Info: Src 13. 1. 1. 2, Dst 13. 1. 1. 4, Tun_Id 1, Tun_Instance 1 RSVP Path Info: My Address: 13. 1. 1. 2 Explicit Route: 10. 1. 1. 2 13. 1. 1. 4 Record Route: NONE Tspec: ave rate=1000 kbits, burst=1000 bytes, peak rate=1000 kbits RSVP Resv Info: Record Route: NONE Fspec: ave rate=1000 kbits, burst=1000 bytes, peak rate=Inf © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 91
MPLS TE Configuration Tunnel 1 GSR 2#sh mpls traffic-eng tunnels name GSR 2_t 1 Name: GSR 2_t 1 Status: Admin: up Oper: up (Tunnel 1) Destination: 13. 1. 1. 4 Path: valid Signalling: connected path option 1, type dynamic (Basis for Setup, path weight 100) Config Paramters: Bandwidth: 1000 Priority: 7 7 Affinity: 0 x 0/0 x. FFFF Auto. Route: enabled Lock. Down: disabled In. Label : Out. Label : POS 2/0, implicit-null RSVP Signalling Info: Src 13. 1. 1. 2, Dst 13. 1. 1. 4, Tun_Id 1, Tun_Instance 1 RSVP Path Info: My Address: 13. 1. 1. 2 Explicit Route: 10. 1. 1. 2 13. 1. 1. 4 Record Route: NONE Tspec: ave rate=1000 kbits, burst=1000 bytes, peak rate=1000 kbits RSVP Resv Info: Record Route: NONE Fspec: ave rate=1000 kbits, burst=1000 bytes, peak rate=Inf © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 92
MPLS TE Configuration Tunnel 2 GSR 2#sh mpls traffic-eng tunnels name GSR 2_t 1 Name: GSR 2_t 2 Status: Admin: up Oper: up (Tunnel 2) Destination: 13. 1. 1. 4 Path: valid Signalling: connected path option 1, type explicit Via. GSR 6 (Basis for Setup, path weight 110) Config Paramters: Bandwidth: 0 Priority: 7 7 Affinity: 0 x 0/0 x. FFFF Auto. Route: enabled Lock. Down: disabled In. Label : Out. Label : POS 3/0, 26 RSVP Signalling Info: Src 13. 1. 1. 2, Dst 13. 1. 1. 4, Tun_Id 2, Tun_Instance 1 RSVP Path Info: My Address: 13. 1. 1. 2 Explicit Route: 10. 1. 1. 10 10. 1. 1. 5 Record Route: NONE Tspec: ave rate=0 kbits, burst=1000 bytes, peak rate=0 kbits RSVP Resv Info: Record Route: NONE Fspec: ave rate=0 kbits, burst=1000 bytes, peak rate=Inf © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 93
MPLS TE Configuration show isis database verbose GSR 2#show isis database verbose GSR 2. 00 -00 IS-IS Level-2 LSP GSR 2. 00 -00 LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL GSR 2. 00 -00 * 0 x 00000009 0 x 5304 1125 0/0/0 Area Address: 49. 0001 NLPID: 0 x. CC Hostname: GSR 2 Router ID: 13. 1. 1. 2 IP Address: 13. 1. 1. 2 Metric: 100 IS-Extended GSR 6. 00 Affinity: 0 x 0000 Interface IP Address: 10. 1. 1. 9 Neighbor IP Address: 10. 1. 1. 10 Physical BW: 622000000 bits/sec Reservable BW: 10000000 bits/sec BW Unreserved[0]: 10000000 bits/sec, BW Unreserved[1]: 10000000 bits/sec BW Unreserved[2]: 10000000 bits/sec, BW Unreserved[3]: 10000000 bits/sec BW Unreserved[4]: 10000000 bits/sec, BW Unreserved[5]: 10000000 bits/sec BW Unreserved[6]: 10000000 bits/sec, BW Unreserved[7]: 10000000 bits/sec © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 94
MPLS TE Configuration show isis database verbose cont’d GSR 2#show isis database verbose GSR 2. 00 -00 [snip] Metric: 100 IS-Extended GSR 4. 00 Affinity: 0 x 0000 Interface IP Address: 10. 1. 1. 1 Neighbor IP Address: 10. 1. 1. 2 Physical BW: 2488000000 bits/sec Reservable BW: 10000000 bits/sec BW Unreserved[0]: 10000000 bits/sec, BW Unreserved[1]: 10000000 bits/sec BW Unreserved[2]: 10000000 bits/sec, BW Unreserved[3]: 10000000 bits/sec BW Unreserved[4]: 10000000 bits/sec, BW Unreserved[5]: 10000000 bits/sec BW Unreserved[6]: 10000000 bits/sec, BW Unreserved[7]: 9000000 bits/sec Metric: 100 IP 10. 1. 1. 8/30 Metric: 100 IP 10. 1. 1. 0/30 Metric: 10 IP 13. 1. 1. 2/32 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 95
MPLS TE IS-IS show commands GSR 2#sh isis mpls traffic-eng ? adjacency-log Adjacency Log advertisements Agent advertisements downstream-tree MPLS TE Optimized Autoroute Calculation downstream tree tunnel Tunnel Information GSR 2#sh isis mpls traffic-eng adjacency-log IS-IS MPLS TE log When Neighbor ID IP Address Interface Status Level 00: 50: 13 GSR 4. 00 10. 1. 1. 2 PO 2/0 Up level-2 00: 50: 12 GSR 6. 00 10. 1. 1. 10 PO 3/0 Up level-2 GSR 2#sh isis mpls traffic-eng tunnel System Id Tunnel Name Bandwidth Nexthop GSR 4. 00 Tunnel 2 0 13. 1. 1. 4 Tunnel 1 1000 13. 1. 1. 4 © 1999, Cisco Systems, Inc. Metric Mode CISCO CONFIDENTIAL - DO NOT DUPLICATE 96
MPLS TE Configuration hostname GSR 4 mpls traffic-eng tunnels ! interface Loopback 0 ip address 13. 1. 1. 4 255 ip router isis SJ ! interface Loopback 5 ip address 192. 168. 5. 1 255. 0 ! interface Ethernet 0 ip address 12. 1. 1. 4 255. 0 ip router isis SJ ! interface POS 2/0 ip address 10. 1. 1. 2 255. 252 ip router isis SJ mpls traffic-eng tunnels ip rsvp bandwidth 1000 © 1999, Cisco Systems, Inc. interface POS 4/0 ip address 10. 1. 1. 5 255. 252 no ip directed-broadcast ip router isis SJ mpls traffic-eng tunnels ip rsvp bandwidth 1000 ! router isis SJ net 49. 0001. 0000. 0004. 00 is-type level-2 -only metric-style wide mpls traffic-eng router-id Loopback 0 mpls traffic-eng level-2 CISCO CONFIDENTIAL - DO NOT DUPLICATE 97
MPLS TE Configuration hostname GSR 6 ! mpls traffic-eng tunnels ! interface Loopback 0 ip address 13. 1. 1. 6 255 ip router isis SJ ! interface POS 4/0 ip address 10. 1. 1. 6 255. 252 no ip directed-broadcast ip router isis SJ mpls traffic-eng tunnels ip rsvp bandwidth 1000 © 1999, Cisco Systems, Inc. interface POS 2/2 ip address 10. 1. 1. 10 255. 252 no ip directed-broadcast ip router isis SJ mpls traffic-eng tunnels ip rsvp bandwidth 1000 router isis SJ net 49. 0001. 0000. 0006. 00 is-type level-2 -only metric-style wide mpls traffic-eng router-id Loopback 0 mpls traffic-eng level-2 CISCO CONFIDENTIAL - DO NOT DUPLICATE 98
MPLS TE Configuration show ip route GSR 2#sh ip route Codes: C - connected, S - static, i - IS-IS, L 1 - IS-IS level-1, L 2 - IS-IS level-2 ia - IS-IS inter area Gateway of last resort is not set S 192. 168. 5. 0/24 is directly connected, Tunnel 2 10. 0/30 is subnetted, 3 subnets C 10. 1. 1. 8 is directly connected, POS 3/0 C 10. 1. 1. 0 is directly connected, POS 2/0 i L 2 10. 1. 1. 4 [115/20] via 10. 1. 1. 10, POS 3/0 [115/20] via 13. 1. 1. 4, Tunnel 2 12. 0. 0. 0/24 is subnetted, 1 subnets i L 2 12. 1. 1. 0 [115/20] via 13. 1. 1. 4, Tunnel 2 13. 0. 0. 0/32 is subnetted, 3 subnets i L 2 13. 1. 1. 4 [115/20] via 13. 1. 1. 4, Tunnel 2 i L 2 13. 1. 1. 6 [115/20] via 10. 1. 1. 10, POS 3/0 C 13. 1. 1. 2 is directly connected, Loopback 0 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 99
8. Basic Troubleshooting • Show Commands • Debugging Commands • Error logs • MPLS TE troubleshooting © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 100
Troubleshooting CLNS Commands show clns int show clns protocol show clns neighbors detail show clns is-neighbors show clns es-neighbors show clns route show clns cache show clns traffic © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 101
Troubleshooting show isis commands show isis spf-log show isis database detail show isis database<lspid> show isis route show isis database L 1|L 2 © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 102
Troubleshooting Debugging Commands debug clns: events CLNS error events filters CLNS filters packets CLNS packet switching activity routing CLNS routing table activity debug isis: adj-packets IS-IS Adjacency related packets checksum-errors IS-IS LSP checksum errors local-updates IS-IS local update packets snp-packets IS-IS CSNP/PSNP packets spf-events IS-IS Shortest Path First Events spf-statistics IS-IS SPF Timing and Statistic Data spf-triggers IS-IS SPF triggering events update-packets IS-IS Update related packet © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 103
Troubleshooting Error Logging log-adjacency-changes Command Used to keep track of changes in the state of adjacent neighbors Helpful in tracking connectivity problems RTX#show log %CLNS-5 -ADJCHANGE: ISIS: Adjacency to 0000. 0001 (ethernet 0) %CLNS-5 -ADJCHANGE: ISIS: Adjacency to 0000. 0002 (ethernet 0) BAD Clns Packet Errors Nov 16 02: 18: 04. 848 EDT: %CLNS-4 -BADPACKET: ISIS: P 2 P hello, option 8 length 53 remaining bytes (51) from VC 2 (ATM 4/0. 2) Nov 16 02: 18: 04. 848 EDT: ISIS: P 2 P hello, option 8 length 53 > remaining bytes (51) from VC 2 (ATM 4/0. 2) © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 104
Troubleshooting SPF Logs RTB#sh isis spf-log Level 1 SPF log When Duration Nodes Count Triggers 00: 25: 27 8 4 1 PERIODIC 00: 18: 09 12 5 2 NEWLSP TLVCONTENT 00: 10: 27 8 5 1 PERIODIC Level 2 SPF log When Duration Nodes Count Triggers 00: 40: 35 8 3 1 PERIODIC 00: 25: 35 8 3 1 PERIODIC 00: 18: 17 8 3 1 TLVCONTENT 00: 10: 34 8 3 1 PERIODIC © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 105
Troubleshooting MPLS TE • Show mpls traffic-eng tunnel • show mpls traffic-eng topology • show mpls traffic-eng autoroute • show mpls traffic-eng link advertisements • show isis traffic-eng tunnels • show isis database [verbose|detail] • show ip rsvp • Debug traffic-eng path calc • debug ip rsvp © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 106
9. Further Reading • ISO 8473 Connectionless Network Protocol (CNLP) • ISO 10589 ISO IS-IS Routing Protocol • ISO 9542 ES-IS Routing Protocol • ISO 8348/Ad 2 Network Services Access Points • RFC 1195 Integrated (Dual) IS-IS • RFC 1237 Guidelines for OSI NSAP allocation in the Internet • http: //www. cisco. com/univercd/cc/td/doc/product/software/i os 113 ed/113 ed_cr/np 1_c/1 cisis. htm • http: //www. cisco. com/univercd/cc/td/doc/product/software/i os 121/121 newft/121 t 3/traffeng. htm © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 107
9. Further Reading • RFC Drafts: • draft-ietf-isis-traffic-02. txt • draft-ietf-isis-3 way-01. txt • draft-ietf-isis-domain-wide-01. txt • draft-ietf-isis-dyname-01. txt • draft-hsmit-mpls-igp-spf-00. txt • draft-ietf-isis-hmac-00. txt © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 108
Q and A • Thank You © 1999, Cisco Systems, Inc. CISCO CONFIDENTIAL - DO NOT DUPLICATE 109
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