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toshi01kudo / SR-MPLS_Multi_AS_MPBGP_Practice

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SR-MPLS と SRv6 環境をeBGPで結んだ際にルート交換が相互の内部ルータでできない #6

Open toshi01kudo opened 3 years ago

toshi01kudo commented 3 years ago

おそらくSRv6側の問題。SRv6環境内部にSR-MPLSのルートが伝搬できない。ASBR同士のPingも不可。

RP/0/RP0/CPU0:cisco-kudo-13#ping vrf UG-A 100.64.10.4 so 100.64.10.3
Wed Dec 30 06:38:43.259 UTC
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 100.64.10.4, timeout is 2 seconds:
.....
Success rate is 0 percent (0/5)
toshi01kudo commented 3 years ago

最初はSR-MPLS側にもルートが伝搬できていなかったが、SRv6側のNext-hop情報の問題だった。 何故かNext-hop情報がバグっており、ac18:2204::という謎のアドレス宛に送るよう依頼していた。 eBGPだが、next-hop-selfを適用して、正常なNext-hop情報になり、ルートが正しく伝搬されるようになった。

バグっている状態：

RP/0/RP0/CPU0:cisco-kudo-01#show bgp vpnv4 uni nei 172.24.34.3 advertised-routes
Wed Dec 30 06:34:27.729 UTC
Network            Next Hop        From            AS Path
Route Distinguisher: 100.64.10.4:10
100.64.10.4/32     172.24.34.4     Local           65091?
Route Distinguisher: 100.64.10.5:10
100.64.10.5/32     ac18:2204::     fd00:5:5::5     65091?
100.64.10.19/32    ac18:2204::     fd00:5:5::5     65091 65019?
172.24.19.0/24     ac18:2204::     fd00:5:5::5     65091?
Route Distinguisher: 100.64.10.6:10
100.64.10.6/32     ac18:2204::     fd00:6:6::6     65091?
100.64.10.29/32    ac18:2204::     fd00:6:6::6     65091 65029?
172.24.29.0/24     ac18:2204::     fd00:6:6::6     65091?
(...snipped...)

Config変更後：

RP/0/RP0/CPU0:cisco-kudo-01(config-bgp-nbr-af)#show comm c d
Wed Dec 30 06:37:31.860 UTC
Building configuration...
!! IOS XR Configuration 7.0.1
   router bgp 65091
    neighbor 172.24.34.3
     address-family vpnv4 unicast
+     next-hop-self
     !
    !
   !
end

RP/0/RP0/CPU0:cisco-kudo-01#show bgp vpnv4 uni nei 172.24.34.3 advertised-routes
Wed Dec 30 06:37:42.113 UTC
Network            Next Hop        From            AS Path
Route Distinguisher: 100.64.10.4:10
100.64.10.4/32     172.24.34.4     Local           65091?
Route Distinguisher: 100.64.10.5:10
100.64.10.5/32     172.24.34.4     fd00:5:5::5     65091?
100.64.10.19/32    172.24.34.4     fd00:5:5::5     65091 65019?
172.24.19.0/24     172.24.34.4     fd00:5:5::5     65091?
Route Distinguisher: 100.64.10.6:10
100.64.10.6/32     172.24.34.4     fd00:6:6::6     65091?
100.64.10.29/32    172.24.34.4     fd00:6:6::6     65091 65029?
172.24.29.0/24     172.24.34.4     fd00:6:6::6     65091?
(...snipped...)
toshi01kudo commented 3 years ago

ASBRからルート情報が共有されているのが見えている。しかし、受信側では受け取りつつも、なぜかActiveなルート情報として出現しない。。

Status codes: s suppressed, d damped, h history, * valid, > best i - internal, r RIB-failure, S stale, N Nexthop-discard Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path Route Distinguisher: 100.64.10.1:10

RP/0/RP0/CPU0:cisco-kudo-02#show route vrf UG-A Wed Dec 30 06:50:58.746 UTC

Codes: C - connected, S - static, R - RIP, B - BGP, (>) - Diversion path D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - ISIS, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, su - IS-IS summary null, * - candidate default U - per-user static route, o - ODR, L - local, G - DAGR, l - LISP A - access/subscriber, a - Application route M - mobile route, r - RPL, t - Traffic Engineering, (!) - FRR Backup path

Gateway of last resort is not set

B 100.64.10.4/32 [200/0] via fd00:4:4::4 (nexthop in vrf default), 00:27:26 L 100.64.10.5/32 is directly connected, 04:15:35, Loopback10 B 100.64.10.6/32 [200/0] via fd00:6:6::6 (nexthop in vrf default), 00:44:52 B 100.64.10.19/32 [20/0] via 172.24.19.9, 01:22:08 B 100.64.10.29/32 [200/0] via fd00:6:6::6 (nexthop in vrf default), 00:44:52 C 172.24.19.0/24 is directly connected, 04:15:22, GigabitEthernet0/0/0/0.19 L 172.24.19.5/32 is directly connected, 04:15:22, GigabitEthernet0/0/0/0.19 B 172.24.29.0/24 [200/0] via fd00:6:6::6 (nexthop in vrf default), 00:44:52