Subject: Regarding Connectivity detection in Demand Mode

From: "Dr. Soumitra Sinha Roy" <[email-masked]>
Date: Fri, 21 Apr 2006 07:45:22 +0100 (BST)

Sir,

In draft-ietf-bfd-base-04.txt, Sec 6.5 Page 19
Paragraph 2 says -
Demand mode requires that some other mechanism is used
to  imply continuing connectivity between the two
systems. The mechanism used does not have to be the
same in both directions and is outside the scope of
this specification.One posible mechanism is the
receipt of traffic from the remote system; another is
the use of the Echo function.

As the draft says the mechanism used does not have to
be the same in both directions, Does this mean that
one system can check connectivity using Echo function
and other system checking the connectivity using Poll
sequence?
For example, In Both RT1 nad RT2 Demand mode bit = 1,
Required Min Echo Rx. interval is non- zero.
At Time t1, RT1 is checking it's connectivity with RT2
using Echo packets. RT2 forwards the ECHo packets back
to RT1.

At time t2, RT2 is checking it's connectivity with RT1
by sending a BFD control packet with Poll bit = 1.
So, RT1 replies to RT2 with BFD control Packet with 
F = 1.

Is this scenario possible?
Can someone explain the mechanism of receipt of
Traffic
from the remote system?

With Regards,
Murti

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