IS-IS for IPv6. ISP Workshops

Transcription

1 IS-IS for IPv6 ISP Workshops These materials are licesed uder the Creative Commos Attributio-NoCommercial 4.0 Iteratioal licese ( Last updated 8 th April

2 Ackowledgemets p This material origiated from the Cisco ISP/IXP Workshop Programme developed by Philip Smith & Barry Greee p Use of these materials is ecouraged as log as the source is fully ackowledged ad this otice remais i place p Bug fixes ad improvemets are welcomed Please workshop (at) bgp4all.com Philip Smith 2

3 Topics Covered p IS-IS stadardisatio p IS-IS for IPv6 p Multi-Topology IS-IS 3

4 IS-IS Stadards History p ISO specifies the OSI IS-IS routig protocol for CLNS traffic p RFC 1195 added IPv4 support Also kow as Itegrated IS-IS (I/IS-IS) I/IS-IS rus o top of the Data Lik Layer p RFC5308 adds IPv6 address family support p RFC5120 defies Multi-Topology cocept Permits IPv4 ad IPv6 topologies which are ot idetical Permits roll out of IPv6 without impactig IPv4 operatios 4

5 Itegrated IS-IS for IPv6 Overview p 2 Type/Legth/Values (TLV) added to support IPv6 routig p IPv6 Reachability TLV (0xEC) Describes etwork reachability such as IPv6 routig prefix, metric iformatio ad some optio bits p IPv6 Iterface Address TLV (0xE8) Cotais a 128 bit address For Hello PDUs, must cotai the lik-local address (FE80::/10) For LSP, must oly cotai the o lik-local address 5

6 Itegrated IS-IS for IPv6 Overview p A ew Network Layer Protocol Idetifier (NLPID) is defied Allowig IS-IS routers with IPv6 support to advertise IPv6 prefix payload usig 0x8E value IPv4 ad OSI uses differet values 6

7 IS-IS for IPv6 7

8 IS-IS for IPv6 p A sigle SPF rus per level for OSI, IPv4 ad IPv6 All routers i a area must ru the same set of protocols [IPv4- oly, IPv6-oly, IPv4-IPv6] L2 routers do t have to be cofigured similarly but o routig hole must exist 8

9 Simple SPF rules p If IS-IS is used for both IPv4 ad IPv6 i a area, both protocols must support the same topology withi this area: o adjacecy-check betwee L2 routers over-rides this, but must be used with cautio p All iterfaces cofigured with IS-ISv6 must support IPv6 p All iterfaces cofigured with IS-IS for both protocols must support both of them IPv6 cofigured tuel wo t work, GRE should be used i this cofiguratio p Otherwise, cosider Multi-Topology IS-IS (separate SPF) 9

10 Sigle SPF IS-IS for IPv6 restrictios p IS-IS for IPv6 uses the same SPF for both IPv4 ad IPv6. p Therefore: Not suitable for a existig IPv4 IS-IS etwork where operator wats to tur o scattered IPv6 support If usig IS-IS for both IPv4 ad IPv6 the the IPv4 ad IPv6 topologies MUST match exactly. Caot ru IS-IS IPv6 o some iterfaces, IS-IS IPv4 o others. Will oly form adjacecies with similarly-cofigured routers. p For example, a IS-IS IPv6-oly router will ot form a adjacecy with a IS- IS IPv4/IPv6 router. (Exceptio is over L2-oly iterface) Caot joi two IPv6 areas via a IPv4-oly area. L2 adjacecies will form OK but IPv6 traffic will black-hole i the IPv4 area. 10

11 IS-IS Hierarchy & IPv6 example Area B Area C Area A Area D IPv4-IPv6 eabled router IPv4-oly eabled router 11

12 Cofigurig IS-IS for IPv6 p CLI is familiar: p IPv6 address family mode eables features specific to IPv6: router isis as64512 et set-overload-bit o-startup wait-for-bgp! address-family ipv6 set-overload-bit o-startup wait-for-bgp! p Cofigure IS-IS for IPv6 o iterfaces Iterface must be IPv6 eabled, eg. IPv6 address set 12

13 IS-IS for IPv6 Specific Attributes (1) p Eterig address-family sub-mode [o] address-family ipv6 p IPv6 address-family sub-mode. [o] adjacecy-check Eables or disables adjacecy IPv6 protocol-support checks. If checkig is eabled (default coditio whe IS-IS IPv6 is cofigured) the the router will ot form a adjacecy with a eighbor ot supportig IS-IS IPv6. [o] distace <1-254> Sets the admiistrative distace of IS-IS IPv6. Note that the admiistrative distace is applied to routes i the IPv6 routig table oly. 13

14 IS-IS for IPv6 Specific Attributes (2) [o] maximum-paths <1-4> Sets the maximum umber of paths allowed for a route leart via IS-IS IPv6. Note that this applies to the IPv6 routig table oly. [o] default-iformatio origiate [route-map <ame>] Cofigures origiatio of the IPv6 default route (::) by IS-IS. Used i the same maer as the existig IPv4 default-iformatio commad. [o] summary-prefix <prefix> [level-1 level-2 level-1-2] Cofigures IPv6 summary prefixes. Commad is used i same maer as the existig IPv4 summary-prefix commad. [o] set-overload-bit o-startup wait-for-bgp Set overload bit so that the router does ot eter trasit path util ibgp is ruig 14

15 IS-IS for IPv6 Specific Attributes (3) [o] redistribute <protocol> [metric <value>] [metric-type {iteral exteral}] [level-1 level-1-2 level-2] [route-map <ame>] Cofigures redistributio of routes leart from other IPv6 sources ito IS-IS. Commad is used i same maer as existig IPv4 redistribute commad. [o] redistribute isis {level-1 level-2} ito {level-1 level-2} distribute-list <prefix-list-ame> Cofigures IS-IS iter-area redistributio of IPv6 routes. Commad is used i same maer as existig IPv4 redistribute isis commad. p Leavig address-family sub-mode exit-address-family p Showig the I/IS-ISv6 cofiguratio show ipv6 protocols [summary] 15

16 IS-IS for IPv6 Cofiguratio Example Area :db8:1::/48 FE0/1 router1 FE0/0 2001:db8:1:1::1/64 router3 FE0/1 2001:db8:1:1::2/64 FE0/0 Area Router1# iterface fastetheret0/0 ipv6 address 2001:db8:1:1::1/64 ipv6 router isis isis circuit-type level-2-oly router isis et address-family ipv6 redistribute static exit-address-family 2001:db8:1::/48 16

17 IS-IS dual stack cofiguratio Router2 LAN1: 2001:db8:1::/64 Etheret 1 Router1 Etheret 2 LAN2: 2001:db8:2:/64 Dual IPv4/IPv6 cofiguratio. Redistributig both IPv6 static routes ad IPv4 static routes. Router1# iterface etheret 1 ip address ipv6 address 2001:db8:1::1/64 ip router isis ipv6 router isis iterface etheret 2 ip address ipv6 address 2001:db8:2::1/64 ip router isis ipv6 router isis router isis et c.00 redistribute static! address-family ipv6 redistribute static exit-address-family 17

18 IS-IS Display (1) router1#sh ipv6 route isis IPv6 Routig Table - default - 46 etries Codes: C - Coected, L - Local, S - Static, U - Per-user Static route B - BGP, HA - Home Aget, MR - Mobile Router, R - RIP I1 - ISIS L1, I2 - ISIS L2, IA - ISIS iterarea, IS - ISIS summary D - EIGRP, EX - EIGRP exteral, ND - Neighbor Discovery, l - LISP O - OSPF Itra, OI - OSPF Iter, OE1 - OSPF ext 1, OE2 - OSPF ext 2 ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2 I2 2001:DB8::2/128 [115/2] via FE80::C801:3CFF:FE4F:8, FastEtheret0/0 I2 2001:DB8::3/128 [115/20] via FE80::C802:3CFF:FE4F:0, Serial1/0 I2 2001:DB8::4/128 [115/22] via FE80::C801:3CFF:FE4F:8, FastEtheret0/0 I2 2001:DB8::5/128 [115/40] via FE80::C802:3CFF:FE4F:0, Serial1/0 I2 2001:DB8::6/128 [115/42] via FE80::C801:3CFF:FE4F:8, FastEtheret0/0 via FE80::C802:3CFF:FE4F:0, Serial1/0 18

19 IS-IS Display (2) router1#sh isis ipv6 rib IS-IS IPv6 process workshop, local RIB * 2001:DB8::2/128 via FE80::C801:3CFF:FE4F:8/FastEtheret0/0, type L2 metric 2 LSP [7/8] * 2001:DB8::3/128 via FE80::C802:3CFF:FE4F:0/Serial1/0, type L2 metric 20 LSP [2/8] * 2001:DB8::4/128 via FE80::C801:3CFF:FE4F:8/FastEtheret0/0, type L2 metric 22 LSP [8/8] * 2001:DB8::5/128 via FE80::C802:3CFF:FE4F:0/Serial1/0, type L2 metric 40 LSP [4/8] * 2001:DB8::6/128 via FE80::C801:3CFF:FE4F:8/FastEtheret0/0, type L2 metric 42 LSP [5/8] via FE80::C802:3CFF:FE4F:0/Serial1/0, type L2 metric 42 LSP [5/8] * 2001:DB8::7/128 via FE80::C802:3CFF:FE4F:0/Serial1/0, type L2 metric 60 LSP [A/8] * 2001:DB8::8/128 via FE80::C801:3CFF:FE4F:8/FastEtheret0/0, type L2 metric 62 LSP [6/8] via FE80::C802:3CFF:FE4F:0/Serial1/0, type L2 metric 62 LSP [6/8]... 19

20 ISIS Display (3) Router2#sh cls is-eighbors detail Tag Workshop: System Id Iterface State Type Priority Circuit Id Format router1 Fa0/0 Up L2 64 Router2.01 Phase V Area Address(es): IP Address(es): * IPv6 Address(es): FE80::C800:3CFF:FE4F:8 Uptime: 00:07:31 NSF capable Iterface ame: FastEtheret0/0 Router4 Se1/0 Up L Phase V Area Address(es): IP Address(es): * IPv6 Address(es): FE80::C803:3CFF:FE4F:0 Uptime: 00:07:32 NSF capable Iterface ame: Serial1/0 Router14 Fa0/1 Up L2 64 Router14.02 Phase V Area Address(es): IP Address(es): * IPv6 Address(es): FE80::C80D:3CFF:FE50:6 Uptime: 00:08:40 NSF capable Iterface ame: FastEtheret0/1 20

21 Multi-topology IS-IS 21

22 Multi-Topology IS-IS extesios p Multi-Topology is used by ISPs who are deployig IPv6 o a existig IPv4 ifrastructure: Ruig sigle topology IS-IS meas that eablig IS-IS IPv6 o a poit to poit lik must be doe simultaeously at both eds p Otherwise the adjacecy will go dow, leadig to possible breakage i the etwork Addig ew routers o a broadcast media i a sigle topology IS-IS is very tricky p IS-IS for IPv6 must be eabled o all devices o the broadcast media at the same time p Otherwise breakage i the etwork could occur due to adjacecies goig dow 22

23 Multi-Topology IS-IS extesios p IS-IS for IPv6 assumes that the IPv6 topology is the same as the IPv4 topology Sigle SPF ruig, multiple address families Some etworks may be like this, but some others may ot be p Multi-Topology IS-IS solves this problem New TLV attributes itroduced New Multi-Topology ID #2 for IPv6 Routig Topology Two topologies maitaied: p ISO/IPv4 Routig Topology p IPv6 Routig Topology 23

24 Multi-Topology IS-IS Restrictios p This feature is ot compatible with the previous sigle SPF model New TLV are used to trasmit ad advertise IPv6 capabilities All routers that ru IS-IS for IPv6 eed to eable multi-topology withi the etwork A trasitio mode is provided for existig IS-IS IPv6 etwork to migrate to Multi-Topology IS-IS IPv6 24

25 Multi-Topology IS-IS Restrictios p IPv4 or IPv6 or IPv4/IPv6 may be cofigured o the iterface for either level-1, level-2 or level-1-2 p If IPv4 ad IPv6 are cofigured o the same iterface, they must be ruig the same IS-IS level IPv4 caot be cofigured to ru o IS-IS level-1 oly o a iterface while IPv6 is cofigured to ru IS-IS level-2 oly o the same iterface. 25

26 Multi-Topology IS-IS Restrictios p All routers o a LAN or poit-to-poit lik must have at least oe commo supported topology (IPv4 or IPv6) whe operatig i Multi-Topology IS-IS mode N.B. a router that is ot operatig i Multi-Topology IS-IS IPv6 mode caot form adjacecy with Multi-Topology IS-IS IPv6 router, eve though IPv6 is the commo supported topology. However, if IPv4 is the commo supported topology betwee those two routers, adjacecy should be formed. p Wide metrics are required to be eabled globally withi the Autoomous System (Default for most ISPs these days ayway) 26

27 Multi-Topology IS-IS example Area B Area C Area A Area D IPv4-IPv6 eabled router IPv4-oly eabled router The Multi-Topology software will create two topologies iside Area: IPv4 ad IPv6. IPv4-oly routers will be excluded from the IPv6 topology 27

28 Multi-Topology IS-IS Cofiguratio example p p Area B LAN1: 2001:db8:1::/64 Etheret 1 Router1 Etheret 2 LAN2: 2001:db8:2::/64 The optioal keyword trasitio may be used for trasitioig existig IS-IS IPv6 sigle SPF mode to MT IS-IS Wide metric is madated for Router1# iterface Etheret 1 ip address ipv6 address 2001:db8:1::1/64 ip router isis ipv6 router isis isis ipv6 metric 20 iterface Etheret 2 ip address ipv6 address 2001:db8:2::1/64 ip router isis ipv6 router isis isis ipv6 metric 20 router isis isp et metric-style wide! address-family ipv6 multi-topology exit-address-family Multi-Topology to work 28

29 Narrow to Wide Metrics Trasitio p Whe migratig from arrow to wide metrics, care is required Narrow ad wide metrics are NOT compatible with each other Migratio is a two stage process, usig the trasitio keyword p Networks usig arrow metrics should first cofigure across all routers: router isis isp metric-style trasitio p Oce the whole etwork is chaged to trasitio support, the metric style ca be chaged to wide: router isis isp metric-style wide 29

30 Multi-Topology IS-IS Display Router2# show cls eighbors detail Tag workshop: System Id Iterface SNPA State Holdtime Type Protocol Router2 Fa0/0 ca01.3c4f.0008 Up 7 L2 M-ISIS Area Address(es): IP Address(es): * IPv6 Address(es): FE80::C801:3CFF:FE4F:8 Uptime: 00:01:46 NSF capable Topology: IPv4, IPv6 Iterface ame: FastEtheret0/0 Router2# show isis database detail Tag workshop: IS-IS Level-2 Lik State Database: LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL router * 0x xD3D /0/0 Area Address: Topology: IPv4 (0x0) IPv6 (0x2) NLPID: 0xCC 0x8E Hostame: router1 IP Address: IPv6 Address: 2001:DB8::1 Metric: 2 IS-Exteded Router2.01 Metric: 20 IS-Exteded Router3.00 Metric: 2 IS-Exteded Router13.02 Metric: 2 IS (MT-IPv6) Router2.01 Metric: 20 IS (MT-IPv6) Router3.00 Metric: 2 IS (MT-IPv6) Router

31 Multi-Topology IS-IS Support p I Cisco IOS: Supported i 12.2SRE, 12.2SXH, 12.4T, ad 15.0 owards The commads for MT are i 12.3 ad 12.4 but do ot work p The oly workaroud is to use sigle topology or chage to the kowig workig releases p I Cisco IOS-XE: Supported i 3.3 or later p I Cisco IOS-XR: Supported i 3.9 or later Note: MT is eabled by default p I Juiper JuOS: Supported i 9.0 or later set protocols isis topologies ipv6-uicast 31

32 IS-IS for IPv6 ISP Workshops 32