The MPLS-OPS Archive[Date Prev][Date Next][Thread Prev][Thread Next] [Date Index][Thread Index][Author Index][Subject Index] Re: IP Routing problem after enabling MPLS?
> Is it just the IOS versions I'm running? How do other people do their > MPLS? I refuse to believe that everybody running MPLS does so only on > either GigE, E3, POS or others, but not FE or Eth ... somewhere I read > that Cisco FEs do not support larger MTUs, but "show cont" will display > a max MTU of 1524 (while GigE has a Max MTU of 1536, but allows for > higher sizes in "conf t" ...) There are many Cisco FE interfaces that do not support higher MTUs than 1500, for instance PAs for 7200. This should not be a problem as long as you only use these on the customer facing side (towards the CE router). On network facing side of your P or PE routers (towards other P and PE routers), you *need* at least 8 byte extra for 2 labels. You can either use a lower IP MTU in your network (ensuring there is room for at least two labels, preferably a bit more), or you can use interface types that support a higher MTU than 1500. Most serial and SONET/SDH interfaces support considerably larger MTUs. There is no magic wand here - if you want to use MPLS, you need room for the labels. Steinar Haug, Nethelp consulting, sthaug@nethelp.no ------- The MPLS-OPS Mailing List Subscribe/Unsubscribe: http://www.mplsrc.com/mplsops.shtml Archive: http://www.mplsrc.com/mpls-ops_archive.shtml
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