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RE: [EFM] OAM loop back / echo server function

Geoff, Roy, and all, please see my message from Friday on this loopback/ping

It is an already-solved problem, via 802.2 LLC TEST PDUs. Testing LLC-to-LLC
connectivity is the very reason for the TEST PDU's existence. Responding to
incoming TEST Command PDUs is mandatory for every Class of LLC client. So
our Ethernet forefathers already provide the solution...sort of. It is just
not used much because only the ability to reply is mandatory. The ability to
send is optional. Most any requirement that is optional is synonymous to
MUST NOT implement :o). So the capability just lies in waiting. It is
arguable whether it is of value in an enterprise network, since every
powered NIC is bound to a full TCP/IP stack. This may not be the case for
EFM. There may be no requirement for support at and above the Network layer
in the EFM ONU, or it may just be a subset, e.g. no TCP. Depends on overall
system partitioning and management functional partitioning.    

The other topics in my message were: BER testing, interleaved time slot
cycles, and extension of LLC XID in lieu of new MAC Control types. I'd
appreciate any comments on these proposals since they each seem to address a
yet-unsolved problem, and all are within the scope of the EFM charter I

-----Original Message-----
From: Roy Bynum [mailto:roy.bynum@xxxxxxxx]
Sent: Tuesday, September 04, 2001 4:06 PM
To: Geoff Thompson
Subject: Re: [EFM] OAM loop back / echo server function


Would a MAC Control frame with a specific opcode  be usable as an L2 
ping.  This would take the frame all the way to the MAC control layer, 
through all of the PHY and RS.

There could also be a command within the OAM functionality that would 
generate a special MAC Control frame that would have an opcode that would 
specify a test pattern in the "parameters" field of the frame.  This could 
potentially provide a very valuable remote trouble shooting tool for 
service providers.

Roy Bynum

At 03:02 PM 9/4/01 -0700, Geoff Thompson wrote:

>I don't think this is a stupid question.
>I don't think we need an IP level PING
>A L2 ping would do, perhaps even better, the demarc would look for PING 
>type and then just swap SA & DA.
>My expectation is that the demarcation device will need a MAC address
>My expectation is that the demarcation device will probably end up with an 
>IP address in order to support:
>         SNMP for OA&M
>         Firewall services for the subscriber
>(That issue is, of course, beyond our scope)
>At 03:47 PM 9/4/01 -0400, Fletcher E Kittredge wrote:
>>On Fri, 31 Aug 2001 14:11:54 -0700  "Geoff Thompson" wrote:
>> > As I have said before, I do believe that we will need a demarcation
>> > that has the capability to host OA&M functions.
>> > We have talked about "loop back" from this point in the network.
>> > Let us forevermore make that "PING"
>>         Apologies if this is a stupid question, but does PING in this
>>context mean the utility that sends an IP ICMP ECHO REQUEST packet and
>>listens for an ECHO REPLY packet?  If so, am I correct in thinking this
>>means the demarcation device would require an IP address?