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Eddie Kohler edited this page Oct 17, 2017 · 2 revisions

DSRArpTable Element Documentation

NAME

DSRArpTable — Click element; Maintains an ARP table for DSR.

SYNOPSIS

DSRArpTable(IP, ETHER)

Ports: 3 inputs, 3 outputs

DESCRIPTION

Packets with ethernet headers pushed into input 2 are sent out unchanged on output 2. I-MAC address entries are added to the ARP table for each pushed packet's source MAC address and source IP address (derived from the various DSR option headers).

Ports 0 and 1 (both agnostic) add a link-level MAC header to incoming packets. Port 0 outputs on port 0, port 1 on port 1. The destination MAC address is found by using the packet's destination IP annotation to lookup the MAC in the ARP table.

Design rant follows (by Doug):

Why two inputs that do exactly the same thing and go to their respective separate outputs? I don't know, but I conjecture it's to allow this element to be used on the output of two separate queues. This is a bad design (I was going to write suboptimal, but it's BAD). The element should be split into two: DSRArpTable (which is agnostic and records I-MAC) mappings from packets flowing through it), and DSRLookupArp (which is also agnostic, takes DSRArpTable element as an argument, and lookups and writes MAC destination addresses for any packet's passing through it based on the entries in DSRArpTable). The advantage of this design is that you can have as many DSRLookupArps as you want, in either push or pull paths. Even better, split DSRArpTable into DSRArpTable, which never even handles packets, and DSRSnoopARPEntry, which takes DSRArpTable as an argument: packets passing through DSRSnoopARPEntry have their I-MAC mappings added to DSRArpTable. Then you can have as many DSRSnoop elements as you like. Actually, the Snoop and ArpTable elements might even be completely generic, and could be shared with regular IP/Ethernet ARP configurations. Of course, this may be all wrong if you want to do buffering/timeouts of packets in DSRLookupARP...

Regular arguments are:

  • IP — This node's IP address.
  • ETHER — This node's ethernet address.

SEE ALSO

DSRRouteTable

Generated by click-elem2man from ../elements/grid/dsrarptable.hh:11 on 2017/10/17.

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