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

[Date: 09/05/2001  From Seto]


I can think of one compelling reason for having L2 ping in MAC 
control which is that service providers do not need to configure
 unique IP address to each demarc box they would provide to 
their subscriber customers.  Better yet, a customer may be able 
to buy a 802.3ah EFM modem at RadioShack and the service 
provider can check the connectivity without the box being 
properly IP configured by the customer.  

If we are talking about P2P configuration only, each demarc 
point may not need a unique MAC address provided we standardize 
one unique MAC control address and EtherType for L2 ping.  At 
least, service providers do not need to know each MAC address of
 each customer's demarc box.  (In this case EPON needs to be P2P


>At 06:05 PM 9/4/01 -0500, Roy Bynum wrote:
>>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.
>This function "could" be added to MAC control.
>It is not clear that there would be any special reason to do so.
>You would have to make a convincing case that there was some special 
>advantage to doing this vs. using an existing, well known protocol. 
>According to my file copy of RFC 1060 (very old version of Assigned 
>Numbers) decimal 36864 (9000 Hex) packet type is assigned to Loopback.
>It is not clear to me that restricting the path of a Loopback/Echo/Ping to 
>just the [MAC Control][MAC][RS][PHY][Medium][PHY][RS][MAC][MAC Control] 
>would be any advantage. After all, the person machine that wants to do the 
>test would have to open a communications path to the testing [MAC 
>Control/OA&M] anyway.
>>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 
>>>> device
>>>> > 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?