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Re: Hardware Broadcast II
Pascal Anelli <[email protected]> writes:
> I have nearly the same question.
> My question is how an agent like arp can use Mac broadcasting?
> I know Classifier/mac implements a broadcasting mechanism in copying
> packet.
> AttachLL (in addnode) is called with sender node and receiver node as
> parameters, i.e. LL component use unicast address
> only. . Morever the link_ member used for routing
> haven't any information concerning a broadcasting address. I don't
> understand how a packet to broadcast is sent from an agent to Mac
> component and If I change $ll set macDA (in attachLL) to a BCAST_ADDR, I
> am not sure if all the arp agent will receive a arp request (broadcasted
> packet)
>
> Thank you for some light on this point
Well, we've made some changes in the current snapshot and e.g. you can
set a variable in Classifier/Mac to broadcast packets no matter what
the address is. Anyhow, if you want to implement ARP, you should
definitely take a look at the snapshot, looking for LAN C++ code
changes and tcl/lan/vlan.tcl
You're right: If you set macDA to BCAST_ADDR, the packet will make it
to every node on the LAN, but it will not be received by every agent,
because node's classifier will not classify it as you want. That's
why I don't think implementing ARP as an agent is a very good idea:
agent is more like an IP entity with the address, port, etc. It seems
that a better place for ARP would be on top of MAC layer or even
inside MAC.
Yuri.