Common addresses

NetworkVeteranNetworkVeteran Member Posts: 2,338 ■■■■■■■■□□
There are about a dozen MAC addresses and a dozen multicast addresses one should recognize. A good example are the multicast IP addresses used by RIP, IGRP, EIGRP, PIM, and OSPF.. or the multicast MAC addresses used by IS-IS, LACP, STP, etc. Many of these are etched in my brain because I work with them often. Some, less so, especially if I haven't troubleshot them lately.

Do you have any good tricks or mnemonics for memorizing these?


  • gorebrushgorebrush Member Posts: 2,741
    I just remember them...

    I think I'm up to about 6 of them. The really nice thing is, the kinds folks who designed IPv6 kept the same numbers, so and = OSPF
    FF02::5 and 6 = OSPF

    I quite like that.
  • NetworkVeteranNetworkVeteran Member Posts: 2,338 ■■■■■■■■□□
    gorebrush wrote:
    The really nice thing is, the kinds folks who designed IPv6 kept the same numbers, so
    Yup! The IPv6 part I don't worry about, besides its unique address ranges (e.g., 6to4, NAT64, etc.).
  • down77down77 Member Posts: 1,009
    There is no secret trick to memorizing this other than practice practice practice! I wish I could give a better answer.
    CCIE Sec: Starting Nov 11
  • NetworkVeteranNetworkVeteran Member Posts: 2,338 ■■■■■■■■□□
    My favorite is IS-IS with its four common MAC addresses!

    09-00-2B-00-00-04, 09-00-2B-00-00-05, 01-80-C2-00-00-14, & 01-80-C2-00-00-15.
  • NetworkVeteranNetworkVeteran Member Posts: 2,338 ■■■■■■■■□□
    Protocol Addresses

    L2 - 01-80-C2-00-00-xx

    00 STP*
    01 Flow Control*
    03 802.1X*
    07 E-LMI
    0E LLDP*
    14 IS-IS L1 IS
    15 IS-IS L2 IS

    L2 - 09-00-2B-00-00-xx

    04 IS-IS All ES
    05 IS-IS All IS

    L3 - 224.0.0.x

    01 All Systems*
    02 All Routers*
    05 OSPF All Routers*
    06 OSPF Designated Routers*
    09 RIP*
    10 IGRP/EIGRP*
    13 PIM*
    18 VRRP*
    22 IGMPv3*

    * = Relevant to CCIE.
  • NetworkVeteranNetworkVeteran Member Posts: 2,338 ■■■■■■■■□□
    Alright! Sounds like not much to do here but to prioritize and double-up my flash cards (solve forward and reverse).

    I will get this down. :)
  • powmiapowmia Users Awaiting Email Confirmation Posts: 322
    In addition to MACs and Multicast addresses, I highly recommend adding ethertypes to your flash cards. Most important are the values 0x806, 0x800, 0x86DD, 0x8100, and the not really 'ether' ethertypes 0x4242, 0x010B and 0xAAAA. Regarding the IPv6 Multicast, you probably won't need these for your CCIE, but they're good reads anyways - RFC 4291 section 2.7.1 ; RFC 3306 ; RFC 3956 (those are the T, P, and R flags, respectively. Sorry if that's a distraction from the relevant.
  • NetworkVeteranNetworkVeteran Member Posts: 2,338 ■■■■■■■■□□
    Great tip! The only etherTypes I had in my cards were 0x8847 & 0x8848. I've now incorporated the others in.
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