On Fri, 27 Apr 2001, Kurt Kayser wrote:
Hi,
Isn't it a lot more cpu-intensive to 'collect' some 1500-byte frames into some larger bucket, reassemble it into a jumbo-frame when the next box has to chop it in order to send it out on a Sonet/PPP/etc interface which might have a smaller MTU again?
Doesn't make too much sense to me. I guess that was Tony's aim as well..
Kurt
Roeland you are talking about jumbo frames from the end system lan, while John is talking about only using the jumbo frames between the routers. My point was that in John's environment the packets will all be 1500 since the packets are restricted to that size just to get to the router with the GE interface. I understand that there are perf gains as long as the entire path supports the larger packets, but I don't understand the claim that having a bigger pipe in the middle helps.
I dont think that anyone discussed doing that... What was being said was that it makes sence to use jumbo frames between routers when they are encapsulating packets from links with a 1500b mtu, so you don't have to reduce your MTU to 1450 or fragment, i.e. endnode-ether-router>tunnel-jumbo_ether-router-jumbo-ether-tunnel>router-eth-end