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Make use of ARP between routers?

Discussion in 'Networks' started by kobem, Jul 23, 2009.

  1. kobem

    kobem Megabyte Poster

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    As you know, a host must use hardware adressing in order to send packets on the local to the destination
    host and this addressing even used communication between routers. Also, data encapsulation thing
    is done in every part of the network world.But, ARP is told to be applied on the local LAN only.

    If ARP is not run during the communication between routers, considering as an example router A and the one directly connected to it , router B , how can router A learn the destination hardware address of router B that time?
     
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  2. jk2447

    jk2447 Petabyte Poster Moderator

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    Mate I don't mean to sound harsh but it seems to me all you do is ask us the answers to your exam questions. Like, not a concept, but literally whats the answer to this. Someone correct me if I'm wrong
     
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  3. UKDarkstar
    Honorary Member

    UKDarkstar Terabyte Poster

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  4. BosonMichael
    Highly Decorated Member Award

    BosonMichael Yottabyte Poster

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    I believe this is covered in Network+.

    <repeat>
     
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  5. JonnyMX

    JonnyMX Petabyte Poster

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    But if NAT is using asynchronous encryption and router A is in the same time zone as router B then DHCP will take care of addressing and so ARP doesn't apply.
     
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  6. zebulebu

    zebulebu Terabyte Poster

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    Good, solid advice there Jonny. I'd also add that if you're using a crossover cable, ARP won't work at all - the pairs are twisted the wrong way. Also bear in mind that the millennium bug affected ARP in a big way - so any device built after the year 2000 should actually use ARP2K instead of plain ARP
     
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  7. BosonMichael
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    BosonMichael Yottabyte Poster

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    That's what Reverse ARP (RARP) is for.

    Dude! Now you're bringing back memories. I had to go around to every... single... workstation... and patch each one manually. What a drag! :blink
     
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  8. jackd

    jackd Megabyte Poster

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    Unrelated but reading these threads by kobem and the replies from people here have really entertained me at 3 in the morning :)

    And this gets rid of that annoying "you have not posted etc..." message yay :biggrin
     
  9. Modey

    Modey Terabyte Poster

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    I'm dissapointed you didn't mention Parallel ARP (PARP) BM. It's not uncommon to hear a PARP when working on a difficult networking issue of this kind. Depending on who did it though, the TTL could be very low indeed ...

    How did you overcome the ping flux variations after the ARP2K limitations became known though? We had to use Harmonic ARP (HARP). Very soothing actually!

    I'm sure there are other variations of ARP, perhaps some of the more experienced network guru's could enlighten us?
     
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  10. Fergal1982

    Fergal1982 Petabyte Poster

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    Theres always:

    Copper ARP (CARP) - but that seemed a bit fishy to me.
    Temporary ARP (TARP) - good for a blanket first application
     
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  11. JonnyMX

    JonnyMX Petabyte Poster

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    Have you tried configuring router A to be the AARP client and router B to use BARP?
    You haven't mentioned why you are using two routers anyway because I can get BBC2 on my box at home without any.
    You may also have been misled by one of those trick questions, and you may find that the answer is something obvious like 'c) You don't need ARP to make TOAST'.

    Zeb made a valid point about ARP2K so I'd contact Cisco and make sure you are using the right specs.

    Or you've just asked another random question then buggered off for three months without reading any of the answers like you usually do...
     
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  12. BosonMichael
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    BosonMichael Yottabyte Poster

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    I wish the TTL were lower, mate... becuase nobody will press ALT-F4 on the troublesome app! ;) :biggrin
     
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