[j-nsp] TCAM full on EX8200?

[Richard A Steenbergen]

On Thu, Oct 13, 2011 at 02:19:40PM +0200, Michele Bergonzoni wrote:
> Il 13/10/2011 13.31, Chen Jiang ha scritto:
> > AFAIK, The EX8200 use SRAM for FIB and TCAM for ACL, that's not like
> > EX2200/3200/4200 that use TCAM for all FIB and ACL.
> 
> > You could vty to line card and try this knob and see what happened:
> > PFEM2(vty)# show shim route lpm-dmm-stats
> 
> Not sure to understand how something can switch data at that speed using 
> SRAM as a FIB, but it's consistent with my TCAM appearing almost empty.
> 
> Anyway, here's the output:
> 
> 
> PFEM2(vty)# show shim route lpm-dmm-stats
> 
> IPV4
> -----
> 
> ShadowIdx: 0    Partition: 0
> 
> numOfUsedBlocks          : 2077            numOfAllocatedBytes      : 48216
> numOfFreeBytes           : 2046640         numOfPickAllocatedBytes  : 48380
> numOfPickAllBlocks       : 2370
> 
> ShadowIdx: 0    Partition: 1
> 
> numOfUsedBlocks          : 320             numOfAllocatedBytes      : 667884
> numOfFreeBytes           : 1427132         numOfPickAllocatedBytes  : 672216
> numOfPickAllBlocks       : 448
> 
> ShadowIdx: 0    Partition: 2
> 
> numOfUsedBlocks          : 17569           numOfAllocatedBytes      : 
> 2083064
> numOfFreeBytes           : 11952           numOfPickAllocatedBytes  : 
> 2083816
> numOfPickAllBlocks       : 22343


EX8200 uses SRAM for forwarding lookups, and TCAM for firewall 
filtering. SRAM is perfectly capable of doing lookups at these speeds, 
and infact is a lot more flexible than TCAM, whereas TCAM is actually 
much better suited for doing high speed packet filtering.

At any rate, your problem is in partion 2. See how you have 2MB 
allocated and only 11k free, while in partition 0 it is almost 
completely unused, and in partition 1 only 667k out of 2MB is used? One 
of your SRAM partitions is full, and thus you can't add more routes to 
the FIB.

Determining exactly how this happened, and how far you need to plant 
your foot up Juniper's ass to get it fixed, is best left as an excercise 
for the reader. All I will say is that they are now selling -ES 
(enhanced scale) linecards for EX8200 which have more SRAM capacity.

-- 
Richard A Steenbergen <ras at e-gerbil.net>       http://www.e-gerbil.net/ras
GPG Key ID: 0xF8B12CBC (7535 7F59 8204 ED1F CC1C 53AF 4C41 5ECA F8B1 2CBC)