CSS arp cache limit

[mikegoldfarb]

I am looking at deploying 2 x CSS11503 (inline redundant) in an environment where it may have to statically route for a large number of hosts. The largest network any interface is directly connected to is a /24, but static routes on the CSS may be needed for up to 32 x /24s. I am interested to know if the requirement to statically route for up to 8192 hosts could max out the arp cache, which I believe is limited to 5k.

Thanks - mike

[Gilles Dufour]

Mike,

you will definitely hit a limit here.

Also, I don't see why you can't create summary route ?

How many interfaces do you have on your CSS ?

G.

[mikegoldfarb]

Thanks Gilles

4 interfaces on the CSS

Summary route - unfortunately not - the /24s we statically route to are distributed in a non-contiguous manner across 6 gateways (this is flagged for change, but not in the timescale we have)

As all statically routed networks (and 95% of hosts)are one or more hops away, I was thinking it would only be directly attached networks with arp entries?

Is this not the case?

thks..

[Gilles Dufour]

I'm really concerned about the size of the routing table.

Even on a router I would be concerned.

The CSS has a strange way of combining routing table and arp table that was inherited from the past when the company was acquired.

We never tested the CSS with such a high amount of routes [static or dynamic].

Therefore I would suggest you to find a way to reduce this routing table to 1000 routes.

Gilles.

[mikegoldfarb]

Sorry Gilles - I misunderstood - the routing can be done at the /24 to /28 level - we should only have a couple of hundred routes at the most.

Our main concern is confirming that it will only be the directly attached networks that will have an arp cache entry.

Mike

[Gilles Dufour]

2-3 hundreds routes is ok. No worries.

Gilles.