Hi Guys, Thanks for handful of tips here. Attached diagram should roughly show the topology (Sorry a bit messed up as GNS3 only have the round and rectangular shape).
I was under a quick impression that the traffic will goes out from s1/0.43 to R1 (via R3 and R2) rather than the directly connected eth0/0. Apparently it wasn't that way after witnessing the entries on sh ip cef. 10.1.12.1 is not directly connected , so the routers are free to choose which way to reach 10.1.12.1. Plenty of thanks again for your assistance. Brgds Benny > Subject: Re: [OSL | CCIE_RS] Local Preference issue. > From: [email protected] > Date: Mon, 27 Feb 2012 20:38:03 +0100 > CC: [email protected]; [email protected] > To: [email protected] > > Hi, > > Good catch. Showing CEF can help a lot. > > Also Benny, you should check your RIB for how you are learning the > 10.1.12.1/32 route. > > Kim > > On Feb 27, 2012, at 7:46 PM, Piotr Jablonski wrote: > > > Hi Benny, > > > > You have a recursive look up. Look at 10.1.12.0 in your cef. This is the > > answer. This node is reachable via 10.1.14.1. You have a destination IP on > > both nodes possibly. > > > > Rgds > > > > Pj > > 27 lut 2012 14:54, "Benny Sumardy" <[email protected]> napisał(a): > > > >> > >> Hi Guys, > >> > >> These are the output of : > >> > >> IGP (RIPv2 for connecting BGP links) : > >> R4#sr | s router rip > >> router rip > >> version 2 > >> network 10.0.0.0 > >> no auto-summary > >> R4# > >> > >> show ip bgp : > >> > >> > >> R4#sib > >> BGP table version is 8, local router ID is 4.4.4.4 > >> 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 > >> *> 1.0.0.0 10.1.14.1 0 400 0 100 i > >> *>i2.0.0.0 10.1.23.2 0 100 0 i > >> *>i3.0.0.0 10.1.34.3 0 100 0 i > >> *> 4.0.0.0 0.0.0.0 0 32768 i > >> * 11.0.0.0 10.1.14.1 0 0 100 i > >> *>i 10.1.12.1 0 400 0 100 i > >> R4# > >> > >> > >> show ip route 11.1.1.1 & longer : > >> > >> R4#sir 11.1.1.1 > >> Routing entry for 11.0.0.0/8 > >> Known via "bgp 200", distance 200, metric 0 > >> Tag 100, type internal > >> Last update from 10.1.12.1 00:07:16 ago > >> Routing Descriptor Blocks: > >> * 10.1.12.1, from 10.1.23.2, 00:07:16 ago > >> Route metric is 0, traffic share count is 1 > >> AS Hops 1 > >> Route tag 100 > >> MPLS label: none > >> R4#sir 11.1.1.1 longer > >> Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP > >> 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 > >> i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 > >> ia - IS-IS inter area, * - candidate default, U - per-user static > >> route > >> o - ODR, P - periodic downloaded static route, + - replicated route > >> > >> Gateway of last resort is not set > >> > >> B 11.0.0.0/8 [200/0] via 10.1.12.1, 00:07:32 > >> R4# > >> > >> show ip cef : > >> > >> R4#sh ip cef > >> Prefix Next Hop Interface > >> 0.0.0.0/0 no route > >> 0.0.0.0/8 drop > >> 0.0.0.0/32 receive > >> 1.0.0.0/8 10.1.14.1 Ethernet0/0 > >> 2.0.0.0/8 10.1.34.3 Serial1/0.43 > >> 3.0.0.0/8 10.1.34.3 Serial1/0.43 > >> 4.0.0.0/8 attached Loopback0 > >> 4.0.0.0/32 receive Loopback0 > >> 4.4.4.4/32 receive Loopback0 > >> 4.255.255.255/32 receive Loopback0 > >> 10.1.12.0/24 10.1.14.1 Ethernet0/0 > >> 10.1.12.1/32 10.1.14.1 Ethernet0/0 > >> 10.1.14.0/24 attached Ethernet0/0 > >> 10.1.14.0/32 receive Ethernet0/0 > >> 10.1.14.1/32 attached Ethernet0/0 > >> 10.1.14.4/32 receive Ethernet0/0 > >> 10.1.14.255/32 receive Ethernet0/0 > >> 10.1.23.0/24 10.1.34.3 Serial1/0.43 > >> 10.1.23.2/32 10.1.34.3 Serial1/0.43 > >> 10.1.34.0/24 attached Serial1/0.43 > >> 10.1.34.0/32 receive Serial1/0.43 > >> 10.1.34.3/32 10.1.34.3 Serial1/0.43 > >> Prefix Next Hop Interface > >> 10.1.34.4/32 receive Serial1/0.43 > >> 10.1.34.255/32 receive Serial1/0.43 > >> 11.0.0.0/8 10.1.14.1 Ethernet0/0 > >> 127.0.0.0/8 drop > >> 224.0.0.0/4 drop > >> 224.0.0.0/24 receive > >> 240.0.0.0/4 drop > >> 255.255.255.255/32 receive > >> R4# > >> > >> Traceroute : > >> R4#trace 11.1.1.1 > >> > >> Type escape sequence to abort. > >> Tracing the route to 11.1.1.1 > >> > >> 1 10.1.14.1 4 msec * 0 msec > >> > >> > >> Did the sh ip route 11.1.1.1, it showed 10.1.12.1 as the next hop. But the > >> cef listed the next hop to 10.1.14.1 (which is directly connected) rather > >> than 10.1.12.1 (few hops away) as commanded by Local-Pref. > >> Absurd, still try to find what's goin on ... Let me know if i still missed > >> anything... > >> > >> > >> Brgds > >> Benny > >> > >> > >> > >>> Date: Mon, 27 Feb 2012 10:32:50 +0530 > >>> From: [email protected] > >>> To: [email protected] > >>> CC: [email protected] > >>> Subject: Re: [OSL | CCIE_RS] Local Preference issue. > >>> > >>> Yes, it would be more specific route directing traffic towards 14.1 as we > >>> believe. Can you check routing table and CEF table for the below one. > >>> > >>> show ip route 11.1.1.1 > >>> show ip cef .. > >>> > >>> venkee > >>> > >>> On 27 February 2012 00:26, Rob Pool <[email protected]> wrote: > >>> > >>>> If it had the same route in an igp an r would show up because the BGP > >>>> route would prevent it from being inserted in the rib. However, a more > >>>> specific route in an igp wouldn't prevent the less specific BGP route > >> from > >>>> being inserted. > >>>> > >>>> Sent from my iPhone > >>>> > >>>> On Feb 26, 2012, at 1:49 PM, <[email protected]> wrote: > >>>> > >>>>> If it had a more specific route from another protocol, wouldn't a "r" > >>>> for "rib failure"show up for the route in the "sh ip bgp" command? > >>>>> > >>>>> Could an ICMP redirect from 10.1.12.1 is causing this? > >>>>> > >>>>> Doug > >>>>> -------- Original Message -------- > >>>>> Subject: Re: [OSL | CCIE_RS] Local Preference issue. > >>>>> From: Rob Pool <[email protected]> > >>>>> Date: Sun, February 26, 2012 10:41 am > >>>>> To: Benny Sumardy <[email protected]> > >>>>> Cc: CCIE ONLINE STUDY LIST <[email protected]> > >>>>> > >>>>> My guess would be that you have a more specific route being provided > >> by > >>>> an igp or static route. > >>>>> > >>>>> Sent from my iPhone > >>>>> > >>>>> On Feb 26, 2012, at 12:05 PM, Benny Sumardy <[email protected]> > >>>> wrote: > >>>>> > >>>>>> > >>>>>> Hi, > >>>>>> > >>>>>> Applied a local pref value for network 11.0.0.0 (as shown below), > >> so > >>>> the best route will prefer 10.1.12.1 (3 hops) than 10.1.14.1 (1 hop). > >>>>>> But when I do a traceroute, the result still gone through > >> 10.1.14.1. > >>>> Can anybody help on what's missing here? Thanks > >>>>>> > >>>>>> Rgds > >>>>>> Ben > >>>>>> > >>>>>> > >>>>>> R4(config-router)#do sib > >>>>>> BGP table version is 7, local router ID is 4.4.4.4 > >>>>>> 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 > >>>>>> *> 1.0.0.0 10.1.14.1 0 400 0 100 i > >>>>>> *>i2.0.0.0 10.1.23.2 0 100 0 i > >>>>>> *>i3.0.0.0 10.1.34.3 0 100 0 i > >>>>>> *> 4.0.0.0 0.0.0.0 0 32768 i > >>>>>> *>i11.0.0.0 10.1.12.1 0 400 0 100 i > >>>>>> * 10.1.14.1 0 0 100 i > >>>>>> R4(config-router)#do trace 11.1.1.1 > >>>>>> > >>>>>> Type escape sequence to abort. > >>>>>> Tracing the route to 11.1.1.1 > >>>>>> > >>>>>> 1 10.1.14.1 12 msec * 0 msec > >>>>>> R4(config-router)#do sir 11.0.0.0 > >>>>>> Routing entry for 11.0.0.0/8 > >>>>>> Known via "bgp 200", distance 200, metric 0 > >>>>>> Tag 100, type internal > >>>>>> Last update from 10.1.12.1 00:01:14 ago > >>>>>> Routing Descriptor Blocks: > >>>>>> * 10.1.12.1, from 10.1.23.2, 00:01:14 ago > >>>>>> Route metric is 0, traffic share count is 1 > >>>>>> AS Hops 1 > >>>>>> Route tag 100 > >>>>>> MPLS label: none > >>>>>> R4(config-router)# > >>>>>> R4(config-router)#do trace 11.1.1.1 > >>>>>> > >>>>>> Type escape sequence to abort. > >>>>>> Tracing the route to 11.1.1.1 > >>>>>> > >>>>>> 1 10.1.14.1 4 msec * 4 msec > >>>>>> R4(config-router)# > >>>>>> > >>>>>> _______________________________________________ > >>>>>> For more information regarding industry leading CCIE Lab training, > >>>> please visit www.ipexpert.com > >>>>>> > >>>>>> Are you a CCNP or CCIE and looking for a job? Check out > >>>> www.PlatinumPlacement.com > >>>>>> > >>>>>> http://onlinestudylist.com/mailman/listinfo/ccie_rs > >>>>> _______________________________________________ > >>>>> For more information regarding industry leading CCIE Lab training, > >>>> please visit www.ipexpert.com > >>>>> > >>>>> Are you a CCNP or CCIE and looking for a job? Check out > >>>> www.PlatinumPlacement.com > >>>>> > >>>>> http://onlinestudylist.com/mailman/listinfo/ccie_rs > >>>> _______________________________________________ > >>>> For more information regarding industry leading CCIE Lab training, > >> please > >>>> visit www.ipexpert.com > >>>> > >>>> Are you a CCNP or CCIE and looking for a job? Check out > >>>> www.PlatinumPlacement.com > >>>> > >>>> http://onlinestudylist.com/mailman/listinfo/ccie_rs > >>>> > >>> _______________________________________________ > >>> For more information regarding industry leading CCIE Lab training, > >> please visit www.ipexpert.com > >>> > >>> Are you a CCNP or CCIE and looking for a job? Check out > >> www.PlatinumPlacement.com > >>> > >>> http://onlinestudylist.com/mailman/listinfo/ccie_rs > >> > >> _______________________________________________ > >> For more information regarding industry leading CCIE Lab training, please > >> visit www.ipexpert.com > >> > >> Are you a CCNP or CCIE and looking for a job? Check out > >> www.PlatinumPlacement.com > >> > >> http://onlinestudylist.com/mailman/listinfo/ccie_rs > >> > > _______________________________________________ > > For more information regarding industry leading CCIE Lab training, please > > visit www.ipexpert.com > > > > Are you a CCNP or CCIE and looking for a job? Check out > > www.PlatinumPlacement.com > > > > http://onlinestudylist.com/mailman/listinfo/ccie_rs > > > > // Freedom Matters > CCIE #29189 > http://www.packet-forwarding.net > > >
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