[c-nsp] Per packet Load balancing

[Rodney Dunn]

> 
> my_router#sh ip cef 2.2.2.134 int
> 2.2.2.128/28, version 446, per-packet sharing
> 0 packets, 0 bytes
>   Flow: AS 0, mask 28
>   tag information set
>     local tag: 4
>   via 2.2.2.2, 0 dependencies, recursive
>     traffic share 1, current path
>     next hop 2.2.2.2, Serial9/1/5.3 via 2.2.2.0/30
>     valid adjacency
>   via 1.1.1.1, 0 dependencies, recursive
>     traffic share 1
>     next hop 1.1.1.1, Serial9/1/3.100 via 1.1.1.1/32
>     valid adjacency
> 
>   0 packets, 0 bytes switched through the prefix
>   tmstats: external 0 packets, 0 bytes
>            internal 0 packets, 0 bytes
>   Load distribution: 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 (refcount 1)
> 
>   Hash  OK  Interface                 Address         Packets  Tags imposed
>   1     Y   Serial9/1/5.3             point2point        6437    none
>   2     Y   Serial9/1/3.100           1.1.1.1    6438    none
>   3     Y   Serial9/1/5.3             point2point        6438    none
>   4     Y   Serial9/1/3.100           1.1.1.1    6438    none
>   5     Y   Serial9/1/5.3             point2point        6438    none
>   6     Y   Serial9/1/3.100           1.1.1.1    6438    none
>   7     Y   Serial9/1/5.3             point2point        6438    none
>   8     Y   Serial9/1/3.100           1.1.1.1    6438    none
>   9     Y   Serial9/1/5.3             point2point        6438    none
>   10    Y   Serial9/1/3.100           1.1.1.1    6435    none
>   11    Y   Serial9/1/5.3             point2point        6437    none
>   12    Y   Serial9/1/3.100           1.1.1.1    6437    none
>   13    Y   Serial9/1/5.3             point2point        6437    none
>   14    Y   Serial9/1/3.100           1.1.1.1    6436    none
>   15    Y   Serial9/1/5.3             point2point        6437    none
>   16    Y   Serial9/1/3.100           1.1.1.1    6437    none
> my_router#

Make sure you always point the static route at the next hop and not
at the interface.  I'm not sure if that's why one shows the next hop
and one shows point2point.

The routes are different in some way:

>   via 2.2.2.2, 0 dependencies, recursive
>     traffic share 1, current path
>     next hop 2.2.2.2, Serial9/1/5.3 via 2.2.2.0/30
>     valid adjacency
>   via 1.1.1.1, 0 dependencies, recursive
>     traffic share 1
>     next hop 1.1.1.1, Serial9/1/3.100 via 1.1.1.1/32
>     valid adjacency

There are 16 buckets and with two paths the has will be 8 for each.

It is exactly equal for the two paths:

Look at the packet counters for each "6438, etc...".

If you are looking at 'sh int' for the rate it's an average so it
takes time to catch up.

> 
> 
> > 
> > >
> > > Thanks - Amol
> > >
> > >
> > > >
> > > >
> > > >
> > > > >
> > > > >
> > > > >
> > > > > On Tue, 7 Sep 2004 22:04:49 +0530, Amol Sapkal <amolsapkal at gmail.com> wrote:
> > > > > > Thanks!
> > > > > > On Tue, 7 Sep 2004 12:20:59 -0400, Rodney Dunn <rodunn at cisco.com> wrote:
> > > > > > > You shouldn't do it that way.
> > > > > > >
> > > > > > > You can configure CEF to do per-packet load
> > > > > > > balancing.
> > > > > > >
> > > > > > > Turn on CEF globally and then on the inbound
> > > > > > > interface feeding the downstream equal cost paths
> > > > > > > do "ip load-sharing per-packet".
> > > > > > >
> > > > > > > Don't leave it like you have it now.  You are process
> > > > > > > switching all the traffic.
> > > > > >
> > > > > >
> > > > > > This works, I checked on the client router interface. The incoming
> > > > > > traffic is load balanced.
> > > > > >
> > > > > > Apologies for asking it here (and not reading it myself), what does
> > > > > > 'ip load-sharing per-packet' actually do?
> > > > > >
> > > > > > >
> > > > > > > Rodney
> > > > > >
> 
> 
> 
> -- 
> Warm Regds,
> 
> Amol Sapkal
> 
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