From: Joe Touch <touch(_at_)ISI(_dot_)EDU>
Of coourse, we disscuss this problem on the switch and router on the same
A router decrements the IP TTL field.
It should also not propagate broadcast IP packets (subnet or all 1's).
(Any other hard requirements?)
It should send and receive some ICMP, e.g. Need-Frag, unlike some
FDDI-Ethernet bridges that IP fragmented but didn't help with MTU
discovery...and the rest of RFC 1812, including RFC 2644.
] From: Grenville Armitage <gja(_at_)UREACH(_dot_)COM>
] >As to the 3 Layer switch and router, both of them work as a distributor
] >based on the IP address. Just some small differents usage and implemention.
] Layer 3 "switch" is marketing drivel for "really fast" (typically
] hardware) router. If it sinks like a duck....
Yes, as "switch" and "layer 2 switch" are salescritter and trade rag
consultant lies for "not slow multi-port Ethernet bridge."
(Lies because they were intended to mislead the suckers into believing
something false, that adding ports or running at wire speed (as some
nominal "bridges" did before there were "switches") changes the nature
of the device.)
} On Sat, 17 Mar 2001, Randy Bush wrote:
} > >> A router decrements the IP TTL field.
} > > It should also not propagate broadcast IP packets (subnet or all 1's).
} > for a non-attached subnet, what is a broadcast packet?
From: Bora Akyol <akyol(_at_)PLURIS(_dot_)COM>
[ Maybe he meant directed broadcast as in 10.10.255.255 ?
I bet that Mr. Bush's point was that a router not connected to any
RFC 1918 networks cannot know whether 10.10.255.255 is a host address
on 10.0.0.0/8 or the broadcast address for 10.10.0.0/16.
Given automatic aggregation, which is even in RIPv2 and RIPv1, how
does a router distinguish the prefix from the host bits?
See also RFC 2644.
Vernon Schryver vjs(_at_)rhyolite(_dot_)com