[j-nsp] End of M-series hardware with BGP Fulltable

[Joerg Staedele]

Hi all,

this could be interesting to a lof ot M-series users: The number of BGP Routes in the global Table is still growing. M-series user should know that all M-series (at least M5,M10,M7i,M10i) have only 8MB of SRAM/SSRAM in their FIB which can hold up to ~550k unique routes no matter how much memory your Routingengine or DRAM (replaceable) the FIB has.

Currently i only know about a enhanced SSB for M20 which is available and has 16MB so this limit will not be reached in the near future but all other (older) models only have 8MB (fixed on the board, not replacable!) and there are no upgrades available (as far as i know).

Example for a M10 Router with RE-3.0 (only 50% mem used):

> start shell
> vty fib
# show jtree 0 memory
Memory Statistics:
    8388608 bytes total (4 banks)
    7980272 bytes used
     408336 bytes free
       8128 pages total
       7884 pages used
        244 pages free
         31 max freelist size

As you see there is already 95% used.

The SRAM/SSRAM is needed for packet forwarding so i think if it's full you have a blackhole-like routing (so the router will eat the packets for prefixes that didn't fit in the memory).

We are currently replacing all M-series by MX-series since there is no other way (unless you dont have a BGP fulltable).

I just wanted to share this info before many people run into problems because of the memory.

HTH,

Kind regards,
 Joerg