From: san (san.study@gmail.com)
Date: Tue Apr 11 2006 - 01:57:15 GMT-3
Hi,
Question:
-------------
Trying to find on what basis did R5 select the best path for network
112.0.0.0 ?
Topology:
-------------
BB3----ebgp---R3 (RRC)--------(RR)R5---------(RRC)R6-----ebgp----BB1
network 112.0.0.0 is a loopback network of BB1. & comes into BGP process
via "network" command in BB1.
R5 is selecting path via 54.1.1.254 via R6. Would like to know why ? Is it
because of Metric to reach advertised next-hop. 54.1.1.254 is lower ? than
204.12.1.254.
Is my guess correct ? I am guessing this because MED, Local Pref, as-path
list etc are same.
Output:
---------
Rack1R5#sh ip bgp
BGP table version is 14, local router ID is 150.1.5.5
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal,
r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*>i28.119.16.0/24 54.1.1.254 0 200 0 54 i
*>i28.119.17.0/24 54.1.1.254 0 200 0 54 i
* i112.0.0.0 204.12.1.254 0 100 0 54 50 60 i
*>i 54.1.1.254 0 100 0 54 50 60 i
* i113.0.0.0 204.12.1.254 0 100 0 54 50 60 i
*>i 54.1.1.254 0 100 0 54 50 60 i
*>i114.0.0.0 54.1.1.254 0 200 0 54 i
*>i115.0.0.0 54.1.1.254 0 200 0 54 i
Rack1R5#
Rack1R5#sh ip bgp 112.0.0.0
BGP routing table entry for 112.0.0.0/8, version 8
Paths: (2 available, best #2, table Default-IP-Routing-Table)
Advertised to update-groups:
1 2
54 50 60, (Received from a RR-client)
204.12.1.254 (metric 2692096) from 183.1.0.3 (150.1.3.3)
Origin IGP, metric 0, localpref 100, valid, internal
54 50 60, (Received from a RR-client)
54.1.1.254 (metric 20) from 150.1.6.6 (150.1.6.6)
Origin IGP, metric 0, localpref 100, valid, internal, best
Rack1R5#
Rack1R5#
Rack1R5#sh ip route 112.0.0.0
Routing entry for 112.0.0.0/8
Known via "bgp 100", distance 200, metric 0
Tag 54, type internal
Last update from 54.1.1.254 00:26:06 ago
Routing Descriptor Blocks:
* 54.1.1.254, from 150.1.6.6, 00:26:06 ago
Route metric is 0, traffic share count is 1
AS Hops 3
Route tag 54
Rack1R5#
Rack1R5#sh ip route 183.1.0.3
Routing entry for 183.1.0.0/24
Known via "connected", distance 0, metric 0 (connected, via interface)
Redistributing via eigrp 100
Advertised by eigrp 100
Routing Descriptor Blocks:
* directly connected, via Serial0/0
Route metric is 0, traffic share count is 1
Rack1R5#sh ip route 150.1.6.6
Routing entry for 150.1.6.6/32
Known via "ospf 1", distance 110, metric 66, type inter area
Redistributing via eigrp 100
Advertised by eigrp 100 metric 10000 100 255 1 1500
Last update from 183.1.0.4 on Serial0/0, 23:55:35 ago
Routing Descriptor Blocks:
* 183.1.0.4, from 150.1.4.4, 23:55:35 ago, via Serial0/0
Route metric is 66, traffic share count is 1
Rack1R5#
Rack1R5#sh ip route 204.12.1.254
Routing entry for 204.12.1.0/24
Known via "eigrp 100", distance 170, metric 2692096, type external
Redistributing via ospf 1, eigrp 100
Advertised by ospf 1 subnets
Last update from 183.1.58.8 on FastEthernet0/0, 23:33:48 ago
Routing Descriptor Blocks:
* 183.1.58.8, from 183.1.58.8, 23:33:48 ago, via FastEthernet0/0
Route metric is 2692096, traffic share count is 1
Total delay is 40400 microseconds, minimum bandwidth is 1544 Kbit
Reliability 255/255, minimum MTU 1500 bytes
Loading 1/255, Hops 5
Rack1R5#
Rack1R5#sh ip route 54.1.1.254
Routing entry for 54.1.1.0/24
Known via "ospf 1", distance 110, metric 20, type extern 2, forward metric
65
Redistributing via eigrp 100
Advertised by eigrp 100 metric 10000 100 255 1 1500
Last update from 183.1.0.4 on Serial0/0, 1d00h ago
Routing Descriptor Blocks:
* 183.1.0.4, from 150.1.6.6, 1d00h ago, via Serial0/0
Route metric is 20, traffic share count is 1
Rack1R5#
-- Thanks & Rgds SAN
This archive was generated by hypermail 2.1.4 : Mon May 01 2006 - 11:41:57 GMT-3