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4208VL Vlan routing peformance

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traty
Occasional Advisor

4208VL Vlan routing peformance

I have a 4208 with a bunch of vlans - I was contemplating turning on routing for 3 of them (since the 4208VL doesn't support ACL's) and use a separate router for vlans that need ACL's.

I know it has 80gb of back plane _Switching_ but what is it for the routing? I currently have a external BSD box that has a gigabit nic doing full 1gb of routing, but I wanted to make sure that if I have it doing the routing it won't cause the switching of other vlans to slow down.

Thanks
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Marco Wessel
Valued Contributor
Solution

Re: 4208VL Vlan routing peformance

The switching and routing are both wire speed. However, whether or not the 4208 will suffice depends on the amount of hosts routed to. The switches have a table of IP <-> MAC mappings, which it uses to route. (This is different from the CAM table with MAC <-> Port mappings.)

So long as this table isn't full, all is shiny and fast because the routing can be done in hardware. However, once this table fills up, the hardware can't do the routing and the switch will fall back to doing routing in software which is, to say the least, sluggish.

If you have a BSD box already routing a gig of traffic, it might not be good enough unless this traffic is generated by few enough hosts to not fill up the host route table. I can't find how large this table is anywhere, so you'll have to ask hp. (I've complained about that to them before.)

Marco Wessel
Valued Contributor

Re: 4208VL Vlan routing peformance

And by wirespeed of course I mean so long as the backplane isn't full.
traty
Occasional Advisor

Re: 4208VL Vlan routing peformance

Ok, from what I'm understanding it won't work for what I need; because it will be passing internet traffic along with vlan traiffic; and that could cause the table to get full. I'll invest in some gig nics and do LACP :) thanks for the info.

Trevor
cenk sasmaztin
Honored Contributor

Re: 4208VL Vlan routing peformance

hi Traty

please send sh run print 4208 switch
cenk

traty
Occasional Advisor

Re: 4208VL Vlan routing peformance

The switch will not do the required level of routing reliably.