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To: cs551@merlot.usc.edu
Subject: Re: CS551 final1 - TTL
Date: Sun, 26 Oct 2008 22:32:01 -0700
From: Bill Cheng <william@bourbon.usc.edu>

Someone wrote:

  > The spec indicates when receive a packet, decrease its TTL by 1 first.
  > Then if TTL = 0, drop it. Is this correct? or should I process it but do not
  > forward it?

In the Peer-to-Peer section, the spec says:

    If a TTL reaches 0, no forwarding should be performed.

In the TTL section, it also says:

   If the TTL is zero, the message is dropped, otherwise it
   is forwarded to the next node.

So, it's inconsistent.  The way this has been explained in
class, the 2nd one is clearly incorrect.  Sorry about the
inconsistency.  It has now been changed to:

   If the TTL is zero, the message is not forwarded to the
   next node [BC: Fixed 9/24/2008].
--
Bill Cheng // bill.cheng@usc.edu <URL:http://merlot.usc.edu/william/usc/>