
最近做工程遇到一个问题:拓扑图的大概是这样的:AS100--cisco7600---cisco6509---cisco7507---AS200。中间的三台设备都在AS300。AS间都起BGP,76与65起IBGP,65与75起IBGP,AS300内的设备也起OSPF。开的时候没有注意,这段时间发现个问题,在65上查看某个目的的路由时(sh ip route ),发现最佳路由来自75,但是在65下的终端使用tracert到目的时,而是走76出去的?
2 q; u$ d d6 m不知道为什么?" |5 L k5 T! ~2 Q) N) q
如下:! q! M% I6 a7 [' }6 m1 L" I
C:\Documents and Settings\alan>tracert 202.96.134.134. W2 A8 ^5 O4 v2 S
Tracing route to 202.96.134.134 over a maximum of 30 hops9 G2 x; s9 T- c
1 <1 ms <1 ms <1 ms 192.168.139.1
. t! k9 }- d9 a% X' o8 `( o 2 <1 ms <1 ms <1 ms 192.168.140.1
9 B3 H" ~; a3 \/ O4 @/ q* Z& m; x9 c 3 <1 ms 2 ms 1 ms 193.77.139.37
/ X% {; u" B4 i- J- m 4 99 ms 1 ms 1 ms 193.77.139.29; e9 i( ^5 ^% \4 A7 q. b6 k+ M4 r
5 <1 ms <1 ms <1 ms 193.77.139.1---76的内网接口. d" I7 h- S3 d! e" G P2 U
6 92 ms 92 ms 92 ms 202.97.5.254 C/ L0 I- m3 C+ ]/ d) q: b
7 93 ms 92 ms 92 ms 202.97.33.177% |/ w0 V- ^7 A4 u, ?9 f Y0 s
8 93 ms 93 ms 92 ms 202.97.33.33
7 }3 N9 P( s) ^ H. E……2 s/ k& I" n r! T. F
8 H/ i0 Y" l) X f' |( m" m/ O193.77.139.9为75的内网接口
# N$ n- n; h @ U* k1 k5 [6509#sh ip route 202.96.134.134
6 b" x" x+ U( T& A( [9 f FRouting entry for 202.96.128.0/19, supernet8 I( U& K V2 ?) F& `5 |
Known via "bgp 300", distance 200, metric 06 Y6 T B4 `; R! h
Tag AS200, type internal
. T; o- w3 }* W. P Last update from 193.77.139.9 3d03h ago
2 f" A. Y3 l! S! { _ Routing Descriptor Blocks:
1 ~: Z; T+ v/ _1 P2 f * 193.77.139.9, from 193.77.139.9, 3d03h ago0 _' o' p8 Z! g4 a0 ~0 F
Route metric is 0, traffic share count is 11 K+ b4 U- q- M+ F/ J
AS Hops 1) @, t4 t6 U& O; W6 A8 W" a( Y
Route tag AS200 |
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