At 02:48 PM 12/11/01, you wrote: >what does an ethernet keepalive packet look like? Who does a router send >one to (especially if connected to a switch). Is it looking for voltage or >something else?
It's not looking for voltage. It's just checking to see that it can send its own frame. The frame format is actually a loopback frame (EtherType 0x9000) from the "Ethernet Configuration Testing Protocol" section of the Ethernet II standard, which was never widely adopted (except by Cisco). Here's a capture of a keepalive frame: Flags: 0x00 Status: 0x00 Packet Length:64 Timestamp: 14:42:20.319000 04/26/2001 Ethernet Header Destination: 00:00:0C:05:3E:80 Source: 00:00:0C:05:3E:80 Protocol Type:0x9000 Packet Data: 46 bytes (all zeros) Note that this is quite different from a serial keepalive which has sequence numbers and ACKs. Priscilla ________________________ Priscilla Oppenheimer http://www.priscilla.com Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=28928&t=28888 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
