Mansoor Khan wrote: > > > > Hi, > > Try changing the MTU to 1526 on all L2 devices within the network and Can`t do, the ethernet ports on my Ciscos don`t allow anything larger than 1500 ... (been there before) ... -gg
Addendum: I put ip tcp adjust-mss 1300 on the customer router - the destination CE router shows incoming packets of size 1340 (which is correct) - therefore I think I shoudl be able to rule out an actual MTU problem ... The FTP transfer now looks like this - I get the connection, the transfer starts with a couple dozen of packets being transfered, then I get nothing for a minute or so, upon which the transfer continues for another batch of packets, then freezes, etc ... I've known this behavior from MTU problems before, but with a packet size of 1340 this shouldn't be the cause ... Could there be another problem involved? Behind the CE router, our customer has a Checkpoint FW (IIRC), could it be a reassemble problem? Any ideas? Tnx, -garry
OK, just a quick followup on the problem ... turns out everything was configured allright ... there was a potential problem lurking in the Windows firewall, but that wasn't the cause ... a computer hooked up directly to the router had the same problems ... We tried with another router (same 836), and everything worked fine with another account. Replaced the config with the live system config, replaced the router - everything up and running ... I got the router here with me now and will check what's going on with it ... Thanks everybody for the hints and ideas ... -gg
> > Try changing the MTU to 1526 on all L2 devices within the > network and > > Can`t do, the ethernet ports on my Ciscos don`t allow > anything larger than 1500 ... (been there before) ... Your ethernet interfaces must be able to support giants/jumbos if you want to pass/switch them. When you look on these ethernet interfaces do you see lots of giants (errors) on the interfaces? If so, there's your problem. --Dan
Hi, Try changing the MTU to 1526 on all L2 devices within the network and Change the MTU (tag-switching mtu 1526) on all routers. Regards, MK -----Original Message----- From: Garry Glendown [mailto:garry <at> regio.net] Sent: 7/Oct/2004 12:00 AM To: mpls-ops <at> mplsrc.com Subject: [MPLS-OPS]: CE-CE MTU Problem ... Hi, after getting just about all the problems worked out (both MPLS connection related and not) and our customer up an running, a new problem came up ... while all "regular" connection going through the DSL dial up router work fine, the MPLS VPN connection of the customer has problems with the MTU (I suspect) - while normal telnet/terminal sessions work fine inside their MPLS VPN, ftp transfers don't ... problem is I can't get a tcpdump from the FTP site (AS400?), so I can't really pinpoint what is happening at the moment ... basic config is: all Cisco routers, MTU 1456 on the DSL link (changed down from 1480 originally used), MTU 1500 on the ethernet on either side of the CE routers, minimum MTU 1500 on the backbone w/ an mpls mtu of 1520 w/ ip(Continue reading)
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