[c-nsp] BGP load balancing with dCEF
Ihsan Junaidi Ibrahim
ihsan.junaidi at gmail.com
Tue Oct 10 08:13:42 EDT 2006
indeed yes, it had disabled itself due to malloc failure. restarting
cef did just fine. this is the output i got
---
rtr-2#sh ip cef 202.75.134.1
202.75.134.1/32, version 87642, per-destination sharing
0 packets, 0 bytes
Flow: AS 0, mask 32
via 203.121.99.2, 4 dependencies, recursive
traffic share 1
next hop 203.121.99.2, Serial5/0/0:0 via 203.121.99.0/30
valid adjacency
via 203.121.99.6, 5 dependencies, recursive
traffic share 1
next hop 203.121.99.6, Serial5/0/1:0 via 203.121.99.4/30
valid adjacency
via 203.121.99.10, 5 dependencies, recursive
traffic share 1
next hop 203.121.99.10, Serial5/0/2:0 via 203.121.99.8/30
valid adjacency
via 203.121.99.14, 5 dependencies, recursive
traffic share 1
next hop 203.121.99.14, Serial5/0/3:0 via 203.121.99.12/30
valid adjacency
0 packets, 0 bytes switched through the prefix
tmstats: external 0 packets, 0 bytes
internal 0 packets, 0 bytes
On 10/10/06, Oliver Boehmer (oboehmer) <oboehmer at cisco.com> wrote:
> Maybe CEF disabled itself.. check for "FIB" log message.. "no ip
> cef"/"ip cef distributed" should do the trick, but it could have quite
> an impact..
>
> oli
>
> Ihsan Junaidi Ibrahim <mailto:ihsan.junaidi at gmail.com> wrote on Tuesday,
> October 10, 2006 2:03 PM:
>
> > This is getting weird, suddenly i'm getting cef not running messages:
> >
> > rtr-2#sh ip cef 202.75.134.1
> > %CEF not running
> > %Prefix not found
> >
> > any clues on how I should treat this symptom? reload the router?
> >
> >
> > On 10/10/06, Oliver Boehmer (oboehmer) <oboehmer at cisco.com> wrote:
> >> Hi,
> >>
> >> thanks for the info.. In your case, you're doing ebgp-multihop with
> >> equal-cost statics over the links, so no need to enable
> >> maximum-paths, you're right. It should work. Can you check "show ip
> >> cef 202.75.130.4 internal" and check the adjacencies of the 16 hash
> >> buckets? You should see all the interfaces.
> >>
> >> oli
> >>
> >> Ihsan Junaidi Ibrahim <mailto:ihsan.junaidi at gmail.com> wrote on
> >> Tuesday, October 10, 2006 1:31 PM:
> >>
> >>> Previously BGP maximum-path is not enabled but I've enabled that
> >>> just before I took the configuration snapshot. My understanding is
> >>> that multipath is only used for peers connected via multiple
> >>> routers which is not the case here.
> >>>
> >>> On 10/10/06, Ihsan Junaidi Ibrahim
> > <ihsan.junaidi at gmail.com> wrote:
> >>>> Hi,
> >>>>
> >>>> The peer interfaces are all located on the same router and so do
> >>>> us. It's an eBGP peering. and the problem is that traffic always
> >>>> flow heaviest on the fourth interface. Most of the time, the first
> >>>> 3 links are idle.
> >>>>
> >>>> Here's the required output:
> >>>> ---
> >>>> rtr-2#sh ip bgp 202.75.130.4
> >>>> BGP routing table entry for 202.75.128.0/19, version 48155320
> >>>> Paths: (3 available, best #2) Advertised to peer-groups:
> >>>> ibgp-neighbor 6453 9534, (received & used)
> >>>> 216.6.121.9 from 216.6.121.9 (66.110.0.81)
> >>>> Origin IGP, localpref 100, valid, external
> >>>> 9534, (received & used)
> >>>> 202.75.134.1 from 202.75.134.1 (202.75.134.1)
> >>>> Origin IGP, metric 0, localpref 100, valid, external, best
> >>>> 2914 9534, (received & used)
> >>>> 203.78.193.57 from 203.78.193.57 (203.78.192.1)
> >>>> Origin IGP, metric 0, localpref 100, valid, external
> >>>> Community: 190972314 190974311 190975304
> >>>> ---
> >>>>
> >>>> rtr-2#sh ip route 202.75.130.4
> >>>> Routing entry for 202.75.128.0/19, supernet
> >>>> Known via "bgp 9930", distance 20, metric 0
> >>>> Tag 9534, type external
> >>>> Last update from 202.75.134.1 00:08:35 ago
> >>>> Routing Descriptor Blocks:
> >>>> * 202.75.134.1, from 202.75.134.1, 00:08:35 ago
> >>>> Route metric is 0, traffic share count is 1
> >>>> AS Hops 1, BGP network version 48155320
> >>>> ---
> >>>>
> >>>> rtr-2#sh ip route 202.75.134.1
> >>>> Routing entry for 202.75.134.1/32
> >>>> Known via "static", distance 1, metric 0
> >>>> Tag 1
> >>>> Redistributing via ospf 100, bgp 9930
> >>>> Advertised by bgp 9930
> >>>> Routing Descriptor Blocks:
> >>>> 203.121.99.2
> >>>> Route metric is 0, traffic share count is 1
> >>>> 203.121.99.6
> >>>> Route metric is 0, traffic share count is 1
> >>>> 203.121.99.10
> >>>> Route metric is 0, traffic share count is 1
> >>>> * 203.121.99.14
> >>>> Route metric is 0, traffic share count is 1
> >>>>
> >>>> On 10/10/06, Oliver Boehmer (oboehmer)
> > <oboehmer at cisco.com> wrote:
> >>>>> cisco-nsp-bounces at puck.nether.net <> wrote on :
> >>>>>
> >>>>>> Hi all,
> >>>>>>
> >>>>>> We're having trouble doing per-destination load balancing on
> >>>>>> outgoing BGP traffic over 4 x E1 links. It's a 7507 (12.0(26)S)
> >>>>>> with dCEF enabled (globally and on the interfaces). Whenever I do
> >>>>>> a show ip cef xxx.xx, there's only 1 next-hop entry instead of 4.
> >>>>>> How do I get all 4 next-hop entries to be installed?
> >>>>>
> >>>>> Are you installing multiple BGP paths into your RIB, i.e. did you
> >>>>> specify "maximum-paths 4" in your BGP config, or how is your
> >>>>> setup? Please show a "show ip bgp <prefix>", "show ip route
> >>>>> <bgp-prefix>" and "show ip route <bgp-next-hop-of-this-prefix>".
> >>>>>
> >>>>> ol
> >>>>>
> >>>>
> >>>>
> >>>> --
> >>>> Thank you for your time,
> >>>> Ihsan Junaidi Ibrahim
> >>>>
> >>>
> >>>
> >>> --
> >>> Thank you for your time,
> >>> Ihsan Junaidi Ibrahim
> >>
> >
> >
> > --
> > Thank you for your time,
> > Ihsan Junaidi Ibrahim
>
--
Thank you for your time,
Ihsan Junaidi Ibrahim
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