MADMAN wrote: > > Stuart Pittwood wrote: > > It has been mooted to me that we might get better performance > from our > > 1Mb line by using HDLC rather than PPP. > > > > > > > > Is this correct? > > HDLC is more efficient so I guess yes.
In what way is HDLC more efficient than PPP? > If I recall > correctly, > (someone will let me know if not;) PPP rides on top of HDLC. I would be glad to correct you. :-) HDLC is really more of an architecture than a specific protocol and there are many derivatives of it. PPP is just one of them, as is Cisco's HDLC. Other derivitaves include LAPB, LAPD, and LLC2. The standard PPP and Cisco HDLC are so similar in frame format you can barely tell them apart. Cisco HDLC encapsulation has: one-byte address field, which is set to 0x0F for most frames one-byte control byte that is always set to 0x00 two-byte protocol type field Guess what PPP has? Essentially the exact same thing: one-byte flag field set to 0x7F one-byte address field, set to 0x11 one-byte control field set to 0xC0 one or two-byte protocol field Both HDLC and PPP also have a control protocol for keeping the link up. HDLC has SLARP. It sends keepalives. PPP has the Link Control Protocol. It brings the link up and send echos and echo replies. Cisco HDLC can also use SLARP to assign an IP address to the other end. PPP has the Network Control Protocols in many different varieties. The IP variety can assign IP addresses. PPP also supports authentication, which Cisco HDLC doesn't. _______________________________ Priscilla Oppenheimer www.troubleshootingnetworks.com www.priscilla.com > > > > > > > > > If so is it just a case of changing the Encapsulation PPP to > > Encapsulation HDLC on both ends of the link? > > Assuming you have a Cisco on both ends, yes. > > > > > > > > > Are there any implications I should be aware of? > > One big advantage of PPP in the ability to authenticate. > Though 1M > seems odd I assume it's a dedicated link and authentication is > not an issue. > > Dave > > > > > > > > > Thanks > > > > > > > > _________________________ > > > > Stuart Pittwood, MCSE > > > > IT Technician > > > > Amery-Parkes Solicitors > -- > David Madland > CCIE# 2016 > Sr. Network Engineer > Qwest Communications > 612-664-3367 > > "You don't make the poor richer by making the rich poorer." > --Winston > Churchill > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=64389&t=64362 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
