Subject: time to wait

From: Ali Boudani <[email-masked]>
Date: Tue, 17 Apr 2001 10:46:45 +0200

hello,
In MASC isnt 48 hours a long time for a time to wait???
what does time to wait mean exactly??
is 48 h mean that if we want to use multicast adresses , we have at
startup to wait 48 hours to begin use the multicast or what ??

Thanx

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From: Pavlin Ivanov Radoslavov <[email-masked]>
Date: Tue, 17 Apr 2001 02:38:52 -0700

> what does time to wait mean exactly??

This large value is for robustness.
Because MASC is designed to be used in an environment with
non-negligible probability for network partitioning, its claim
period has the conservative value of 48 hours. In most cases it
takes less than 24 hours for an Internet Service Provider to fix a
network-related problem such as intra or inter-domain partitioning.
Hence, waiting for 48 hours should be long enough to ensure the
end-to-end claim propagation, and therefore the uniqueness of the
allocation.

> startup to wait 48 hours to begin use the multicast or what ??

Only when you start MASC for a very first time in your domain. After
that the allocation to the application should not be affected
by the MASC operation. MASC is inter-domain allocation; within a
domain there are AAP/MADCAP which are much faster. After a prefix is
allocated to a domain (MASC always tries to stay ahead of the usage
by allocating the prefix(es) in advance), then AAP+MADCAP use this
prefix to allocate the particular addresses to the
application. MADCAP is a DHCP-style protocol, and it will allocate
the mcast address(es) to the application with similar latency
(within few seconds, if not faster).

Pavlin

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From: Ali Boudani <[email-masked]>
Date: Tue, 17 Apr 2001 11:45:51 +0200

ok I understood
But care should take now of how much time the adresses are allocated to
the same domain.
if an address is allocated to a domain and after a while we didnt use
this adress, of course the domain will loose the allocated domain address
so in this case we have also to wait 48 hours again ???
is that true?
thanx

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From: Pavlin Ivanov Radoslavov <[email-masked]>
Date: Tue, 17 Apr 2001 03:02:20 -0700

> so in this case we have also to wait 48 hours again ???

If the allocated prefix is under-utilised (e.g., under 50%), when it
is close to expire, MASC will reclain only some part of the original
prefix such that the renewed prefix will be reasonably
utilised. If after time the usage of mcast addresses in this domain
goes to zero (and is zero for long amount of time, to say few
months), then MASC may "return" (by not reclaiming it) the original
prefix, and will keep renewing only a small prefix for that domain
(to say, of the order of 256 addresses or even smaller). If the
demand for addresses increases, then MASC will try to allocate a
larger prefix before it is really needed.

BTW, the above description is not part of the MASC protocol, but is
one possible algorithm of how to keep the address space reasonably
utilised, and at the same time to "stay ahead" of the demand for
addresses (and therefore avoid the application waiting for 48
hours).

Pavlin