The IPX header has a "transport control" field which is really a "hop count." The sender sets it to zero. Each router adds one to it.
Novell documentation used to show it as a 4-bit field with 4 bits reserved before it. Recent documentation shows it as an 8-bit field. Older document ion said a router would trash a frame if it arrived with a transport control field already at 15 (0xFFFF). Recently I read this weird thing on Novell's site: A RIP router discards the packet if the value in this field is greater than 15. An NLSP router discards the packet if the value in this field is greater than the value of the Hop Count Limit parameter, which is 127 by default. Is this believable? From what we know about the router having two separate tasks (forwarding and learning the topology), I think the hop-count limits happen when installing routes. I could believe that RIP and NLSP are different. But when a router goes to forward a frame, is it really going to behave differently with respect to hop count if it's running NLSP versus RIP? Does it even care which protocol installed the route. The FIB probably wouldn't even say which protocol installed the route? Chuck likes to remind us about these differences so maybe he has some comments. Thanks Priscilla ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=23389&t=23389 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
