[c-nsp] BGP load balancing with dCEF

[Oliver Boehmer (oboehmer)]

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