[j-nsp] BGP load balancing on 2 links (same ISP)

[Alexander Tarkhov]

On 3/17/07, David Ball <davidtball at gmail.com> wrote:
>    when doing the hashing.  I haven't tried it yet personally, but it
> likely comes with a CPU hit of some kind.
>
> David


Hi David,

There is no CPU hit associated with the hash-key statements on M/T-series.
In fact hardware always uses hashing when load balancing is enabled by
"load-balance per-packet" policy action.

Hash-key stanza gives you choice of data that is used by hash function.
When no hash-key statement configured only Layer 3 header contents is
used by default. Sometimes you notice unequal load distribution
pattern for some kinds of traffic then you are encouraged to tune data
selection for hash-key. There is no performance hit as far as I know.

http://www.juniper.net/techpubs/software/junos/junos82/swconfig82-policy/html/policy-actions-config11.html

-Alexander