Ok this is probably an easy one but where do you get the # 320 from for the fragmentation size?
map-class frame-relay DLCI_403frame-relay cir 256000frame-relay bc 2560frame-relay fragment 320
bc = 2560 bits aka 320 Bytes
ugh, I knew it was something that easy!
In my defence, I didn't have the fragmentation command on the IOS I was using, so I couldn't have seen it was in bytes :P
I must be missing something here. It says in the requirements to decrease the serialization delay as much as possible while making sure that a single packet cannot take more than one interval to be transmitted. I think a typical max for Frame Relay is 1600 bytes. where do they come up with 320 bytes? They create the 10 ms interval which would be ideal for voice but totally ignore the requirement to transmit a single packet per interval. 1600 bytes would be 12800 bits or a 50 ms interval wouldn't it?
I know I must be wrong but I am not understanding the logic here.
"a single packet cannot take more than one interval to be transmitted"
Each interval (bc) is 2560 bits, so you fragment to 2560bits (320 bytes).
fragment size is 80 bytes per 64k of line speed 256/64 = 4 , 4x80 = 320