Well, the RFC does say that consenting PPPs can use other values. Is that like consenting adults?
I've been wondering about larger MTUs though. I mentioned this issue in another message today. A lot of novices think that having a large interface MTU is going to make a big difference, but I'm not convinced. The interface isn't going to combine packets it receives into larger packets just because of the larger MTU. Packets can't grow!? The applications would have to be reconfigured to use larger packets sizes too. They may use MTU discovery, but I bet a lot of applications that have a legacy of running on Ethernet and the Internet either don't do MTU discovery or don't even attempt a very large packet size. I'll have to look into this. Thoughts? Comments? Priscilla At 05:26 PM 11/29/01, Howard C. Berkowitz wrote: > >Found this in RFC 1661 which documents PPP: > > > >The maximum length for the Information field, including Padding, but not > >including the Protocol field, is termed the Maximum Receive Unit (MRU), > >which defaults to 1500 octets. By negotiation, consenting PPP > >implementations may use other values for the MRU. > > > >P. > >Hmmm...I definitely am aware of providers using 4470 on POS links, >and a general trend in the gigabit-plus world to use larger MTUs. Is >this simply industry practice, I wonder, or are there some overriding >IEEE or IETF documents? Perhaps in the sub-IP area, such as IP over >Optical? > > > > >At 03:05 PM 11/29/01, Howard C. Berkowitz wrote: > >> >Howard, > >> > > >> >Correct me if am wrong but, the HDLC advantage over PPP is the MTU size. > >> >PPP supports 1500 while HDLC 4xxx (can't remember the exact number), > >> >this might be helpful in situations where DF bit is set. > >> > > >> >Nabil > >> > >>I'd have to research this -- I don't offhand remember PPP (as the > >>protocol) having a MTU limit that small. It would surprise me, given > >>the interest in POS. > >________________________ > > > >Priscilla Oppenheimer > >http://www.priscilla.com ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=27754&t=27637 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
