From: Scott Morris (swm@emanon.com)
Date: Mon Feb 07 2005 - 16:20:39 GMT-3
This would definitely fall within the "vast collection of useless
knowledge"... :)
The IEEE 802.3 group doesn't actually specify what specific pattern
indicated a "jam signal". So vendors kinda come up with their own thing.
And it basically boils down to a 48 bit pattern of alternating 0's and 1's.
Depending on which one you catch first, this shows up as 5's or A's in a hex
decode.
As a trivial bit of knowledge, the bit pattern in fast ethernet is
different. Instead of using basic Manchester encoding, 100 meg ethernet
uses 4B5B encoding. So the hex pattern is D0 and 43 patterns. It's still
an alternating 010101 (or 101010) pattern, just a different encoding!
Now, the question back to you is why would you possibly care to know
this?!?!? (grin)
Scott Morris, MCSE, CCDP, CCIE4 (R&S/ISP-Dial/Security/Service Provider)
#4713, JNCIP, CCNA-WAN Switching, CCSP, Cable Communications Specialist, IP
Telephony Support Specialist, IP Telephony Design Specialist, CISSP
CCSI #21903
swm@emanon.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Drew
Whitaker
Sent: Monday, February 07, 2005 1:47 PM
To: Cisco certification
Subject: OT: Jam Signal
Anyone know what the bit pattern is for the 48-bit jam signal sent when a
collision occurs on a shared Ethernet segment?
This archive was generated by hypermail 2.1.4 : Thu Mar 03 2005 - 08:51:17 GMT-3