Routers and CRC

Talic

Does each router execute a CRC on the fame as it goes through the PPP WAN?



I would think it would but I'm not sure, I believe the book said it the routers decapsulates the fame so I would think it gives a CRC check. Also, doesn't the routers replace the source MAC address with their own?[/img]

wbosher

From what I understand the PPP frame does have FCS field which checks for errors as it enters the routers interface. There are no MAC addresses on serial interfaces like the ones in your diagram, the address field is set to a broadcast address as the is only one source and one destination address, no need for MAc addresses.

What I'm curious about, is how you pasted that diagram into your message.

Slowhand

wbosher wrote:

What I'm curious about, is how you pasted that diagram into your message.

Like everyone else that likes posting pictures on forums, social networking sites, and other places, I'm guessing Photobucket.com was involved.

Hint: right-click the image and select 'Properties' to see the URI of the image file.

networker050184

Like wbosher stated the FCS is checked at each router along the path.

Also like wbosher stated the address field is set to all ones (11111111 = broadcast) as there is no need for an address when there are only two ends to a ppp link.

So yes, wbosher you understand correctly

(unless my understanding is off also)