3.2 Multicast Basics Issue

A task needs to be added to create an ipv6 address for R6's vlan 46 interface to be 2001:CC1E:X:404::/64 eui-64.  I was unable to get R5 to successfully ping FF06::6 without this.

After looking at the debug ipv6 icmp for R6 was src its echo-reply from it's link-local address.  And R4 would then send dest unreachable back to R6.

See below from R6 debug:

ICMPv6: Received echo request, Src=2001:CC1E:27:4545::5, Dst=FF06::6
ICMPv6: Sent echo reply, Src=FE80::219:56FF:FED4:F922, Dst=2001:CC1E:27:4545::5
ICMPv6: Received Unreachable code 2, Src=FE80::21A:6CFF:FE6B:D39B, Dst=FE80::219:56FF:FED4:F922

Comments

  • Thanks for the help.. same issue resolved by this.

  • Hey, if you take a look at the question you'll see that you don't need to add addresses because you only need to show that the traffic is arriving at R6.

    Recall that in the real lab you can't create new addresses unless told to.

    Cheers.

  • And if you're doing this on Dynamips you'll find that nothing works correctly until you configure an EIGRP adjacency between R6 and R4.

    To do so I actually added the 'illegal' IPv6 address:

     


    Rack1R6(config)#ipv router ei 45

    Rack1R6(config-rtr)#no shut

    Rack1R6(config-rtr)#int fa0/0

    Rack1R6(config-if)#ipv ei 45

    Rack1R6(config-if)#ipv add 2001:cc1e:1:404::6/64

    Rack1R6(config-if)#ipv en

    Rack1R6(config-if)#exit

    Rack1R6(config)#ipv unicast-routing 

    Rack1R6#sh ipv ei int

     

    IPv6-EIGRP interfaces for process 45

     

                            Xmit Queue   Mean   Pacing Time   Multicast    Pending

    Interface        Peers  Un/Reliable  SRTT   Un/Reliable   Flow Timer   Routes

    Fa0/0              0        0/0         0       0/1            0           0

    Rack1R6#

    *Mar  1 08:58:57.849: %DUAL-5-NBRCHANGE: IPv6-EIGRP(0) 45: Neighbor FE80::C000:DFF:FE4E:1 (FastEthernet0/0) is up: new adjacency

    Rack1R6#

    Rack1R6#sh ipv ei int

    IPv6-EIGRP interfaces for process 45

     

                            Xmit Queue   Mean   Pacing Time   Multicast    Pending

    Interface        Peers  Un/Reliable  SRTT   Un/Reliable   Flow Timer   Routes

    Fa0/0              1        0/0        26       0/1           50           0

    Rack1R6#

    Rack1R6#sh ipv mrou

    Multicast Routing Table

    Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, 

           C - Connected, L - Local, I - Received Source Specific Host Report,

           P - Pruned, R - RP-bit set, F - Register flag, T - SPT-bit set,

           J - Join SPT 

    Timers: Uptime/Expires

    Interface state: Interface, State

     

    (*, FF06::6), 01:39:18/never, RP 2001:CC1E:1:505:C001:DFF:FE4E:0, flags: SCLJ

      Incoming interface: FastEthernet0/0

      RPF nbr: FE80::C000:DFF:FE4E:1

     

    (2001:CC1E:1:4545::5, FF06::6), 00:00:06/00:03:23, flags: SJT

      Incoming interface: FastEthernet0/0

      RPF nbr: FE80::C000:DFF:FE4E:1

     

    If you then remove the IPv6 address on R6 you can see the output shown in the WB.

     


    Rack1R6(config)#int fa0/0

    Rack1R6(config-if)#no ipv add

     

    Rack1R6#deb ipv icm

    ICMP packet debugging is on

    Rack1R6#

    *Mar  1 09:03:25.645: ICMPv6: Received echo request from 2001:CC1E:1:4545::5

    *Mar  1 09:03:25.649: ICMPv6: Sending echo reply to 2001:CC1E:1:4545::5

    Rack1R6#

    *Mar  1 09:03:27.389: ICMPv6: Received echo request from 2001:CC1E:1:4545::5

    *Mar  1 09:03:27.393: ICMPv6: Sending echo reply to 2001:CC1E:1:4545::5

    Rack1R6#

    *Mar  1 09:03:29.905: ICMPv6: Received echo request from 2001:CC1E:1:4545::5

    *Mar  1 09:03:29.909: ICMPv6: Sending echo reply to 2001:CC1E:1:4545::5

    Rack1R6#

    *Mar  1 09:03:31.673: ICMPv6: Received echo request from 2001:CC1E:1:4545::5

    *Mar  1 09:03:31.673: ICMPv6: Sending echo reply to 2001:CC1E:1:4545::5

    Rack1R6#

    *Mar  1 09:03:33.305: ICMPv6: Received echo request from 2001:CC1E:1:4545::5

    *Mar  1 09:03:33.305: ICMPv6: Sending echo reply to 2001:CC1E:1:4545::5

    Rack1R6#

    *Mar  1 09:03:34.949: ICMPv6: Received ICMPv6 packet from FE80::C000:DFF:FE4E:1, type 136

    Rack1R6#

    *Mar  1 09:03:39.413: ICMPv6: Received ICMPv6 packet from FE80::C000:DFF:FE4E:1, type 135

    Rack1R6#sh ipv int bri

    FastEthernet0/0            [up/up]

        FE80::C002:DFF:FE4E:0

    Serial0/0                  [up/up]

    FastEthernet0/1            [up/up]

    Serial0/1                  [administratively down/down]

    Loopback0                  [up/up]

    Tunnel0                    [up/up]

        unassigned

    Tunnel1                    [up/down]

        unassigned

    Rack1R6#



    Hope this helps others.



  • Task 3.1 stated "Enable EIGRPv6 on VLAN 46," so I enabled eigrp on R6 fast 0/0 without adding and IPv6 address to the interface, since ipv6 enable is added to the interface a local link is created just enough for eigrp to come up against R4 and ping to ff06::6 works ok from R5.

     

  • I didn't think about just to arrive, can reach R6... yes they reach R6, I hate when I don't understand the question and start doing stuff I shouldn't

  • I do agree with PinGorilla, R6 needs an IPv6 address on VLAN 46;however, it's mainly for the MLD join towards R4. The task does state "ensure multicast packets from R5 can reach R6" and not ensure R5 can ping R6.

     

     

    A task needs to be added to create an ipv6 address for R6's vlan 46 interface to be 2001:CC1E:X:404::/64 eui-64.  I was unable to get R5 to successfully ping FF06::6 without this.

    After looking at the debug ipv6 icmp for R6 was src its echo-reply from it's link-local address.  And R4 would then send dest unreachable back to R6.

    See below from R6 debug:

    ICMPv6: Received echo request, Src=2001:CC1E:27:4545::5, Dst=FF06::6
    ICMPv6: Sent echo reply, Src=FE80::219:56FF:FED4:F922, Dst=2001:CC1E:27:4545::5
    ICMPv6: Received Unreachable code 2, Src=FE80::21A:6CFF:FE6B:D39B, Dst=FE80::219:56FF:FED4:F922

    .

     

     

     

  • I had the same issue and I'm using real equipment.  I've been following the book and what bugs me is the solution in the books shows it working which I know now to be incorrect.

    I was about to get echo reply's going but only with an IPV6 address on R6.  I was only able to get R5 replies by adding ipv6 eigrp onto R6.

    I'm still a bit confussed by where the ICMPv6: Sent N-Solicit is coming from in the solution but since I"m not the best on IPV6 multicast I will wait until I go through the lab a 2nd time.

    Andy

  • Did this task tonight and, just for my own edification i put a routable ipv6 address and a static default pointing at r4 so i could see ping replies on r5.

     

    As mentioned above the sg shows ping replies which should not be possible without a routable address and some kind of route on r6 pointing back at r4, either static or learned by adding the interface to eigrp as 45.

     

    This one seemed less than crystal clear, glad to see I'm not the only one who was a bit baffled by it.

     

     

     

Sign In or Register to comment.