At 09:52 AM 10/4/01, Marty Adkins wrote: >The reason that "show int" only displays the IP encapsulation is the >same reason that only the IP address (and mask) are displayed, not >all layer three addresses -- history. The cisco (sic) product line >started out as only an IP router, so all displays and config commands >were understood to apply to IP.
That makes sense, but I'm wondering about the history... We always hear the story of the Stanford departments needing to talk to each other and I always assumed they had multiprotocol requirements. I do know this much. My husband helped Cisco add AppleTalk in about 1989. It was before they went public, I know that. ;-) >As bridging and other routed protocols >were added, the old commands and displays remained the same for backward >compatibility. E.G., the command to change encapsulation for IP is >just "encapsulation __", not "ip encapsulation __". You can't change the encapsulation for IP. You should try it. We had this discussion before... You can change the encapsulation for ARP. Our theory last time we had this discussion was that most implementations of IP use Ethernet Version II, but a few implementations use SNAP. A Cisco router sends IP frames using the Ethernet Version II frame format, unless it receives IP frames in the SNAP format. If the router sees that a station is using SNAP frames for IP, the router sends SNAP frames. But, before the router can send an IP frame to a destination, it must find the MAC address using ARP. In order to reach a station configured for SNAP, the router must send the ARP using SNAP. Priscilla > And even before >IP really took off, it was needed for managing the routers (Telnet, etc.), >even if the overall enterprise had no use for IP. > >- Marty ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=22063&t=21945 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
