Hello there,
dolejh wrote:If I allow jumbo frames on the MPLS link. Does that mean that all traffic uses jumbo frames?
No.
dolejh wrote:Does normal workstation traffic that is using standard frames get changed to a jumbo frame before transmit.
No.
dolejh wrote:
My assumption was that you only allow jumbo frames where it is really needed. If allowing jumbo frames within the network does not impact standard frame traffic - what is the downside of allowing it everywhere ?
You need to allow it end-to-end "where it is really needed" meaning from src Server 1 to first-hop switch, then along the whole path to the dst Server2 including the link between dst Server2 and last-hop switch.
The known downsides are:
1/ head-of-line blocking (google it)
2/ not all network gear is uniform in supporting jumbo frames/large MTU so You need to find the lowest commonly supported jumbo frame size Yourself. Juniper kit uniformly support 9216 B MTU , and recent linecards (MX MPC7 & newer) support 16KB MTU.
3/ service providers do not uniformly support jumbo frames, You need to talk to Your SP - e.g. if You use pseudowires across different SP as leased line equivalent - what is the max MTU supported less all overheads.
HTH
Thx
Alex