[c-nsp] 9K ATM Link

[Baek, Steven A (US SSA)]

Cisco-Elites,

 

I am having some issues getting layer 7 connectivity between unix lane clients <-over 9k mtu-> to standard ethernet clients and unix lane clients.

Setup is as follows:

 

Unix Client A <--OC3-->Marconi Switch <--OC12-->Cisco 6509 (WS-X6101-OC12MM)<--GigE-->Cisco 6509 (WS-X6101-OC12MM)<---->Marconi Switch<--OC3--> Unix Client B

 

There is something particular about 9k mtu sized traffic that is a requirement for this test. Client A joins an élan hosted by the first Marconi switch and can then ping Client B w/ 18k sized mtu packets. When I try to FTP from Client A to Client B, I can log in, but when I try to xfer data, it hangs. Has anyone seen this before? The DF flag is set, and I don't believe ATM can send fragments. The 6509 blades have a max mtu size of 9216, but the Marconi élan the clients join is set at 9232. Could this be the issue at hand? 

 

The Cisco mtu size is maxed out and the Marconi mtu size is fixed. Jumbo-frames are enabled. 

 

Steve