From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Wed Jun 08 2005 - 13:36:54 GMT-3
If you understand how layer 3 to layer 2 resolution works on
multipoint interfaces and how IPv4 proxy ARP works then it the same
logic that applies to ICMPv6 proxy ND. The problem with ICMPv6 proxy ND
is that the router would have to join the solicited node multicast
address for the address it is proxying for. This works fine for mobile
IPv6 where you know which address you need to proxy for, but it is not
feasible to proxy for all addresses. For IPv4 proxy ARP this is fine
because the ARP request is broadcast. For ICMPv6 ND the address used is
multicast.
HTH,
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
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> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> ccie2be
> Sent: Wednesday, June 08, 2005 10:56 AM
> To: Group Study
> Subject: ipv6 - proxy ICMP ND not supported
>
> Hi guys,
>
> IPv6 is configured between R4 and R6. R4 is running RIPng on it's
other
> interfaces (not shown) but is not running any ipv6 routing protocol on
> it's
> e0/0 int.
>
> R4 e0/0 ------------- e0 R6
>
> R6 is configured with a static default route pointing out it's e0
> interface
> (towards R4).
>
> ipv6 route ::/0 e0
>
> R6#sh ipv6 route
> IPv6 Routing Table - 4 entries
> Codes: C - Connected, L - Local, S - Static, R - RIP, B - BGP
> Timers: Uptime/Expires
>
> L 2001:144:3:46:260:83FF:FE7C:969/128 [0/0]
> via ::, Ethernet0, 03:28:02/never
> C 2001:144:3:46:260:83FF:FE7C:969/64 [0/0]
> via ::, Ethernet0, 03:28:02/never
> L FE80::/64 [0/0]
> via ::, Null0, 03:28:02/never
> S ::/0 [1/0]
> via ::, Ethernet0, 03:28:00/never
>
> Yet, in order for R6 to reach other ipv6 addresses in the network, it
> needs
> to have lots of static L3 to L2 maps configured like this.
>
> ipv6 neighbor 2001:144:3:24:2D0:BAFF:FEE3:2CA0 e0 0002:165a:52a0
>
> BTW, there's no special about e0's ipv6 config:
>
> interface Ethernet0
> ip address 144.3.46.6 255.255.255.0
> ipv6 address 2001:144:3:46::/64 eui-64
>
> The explanation given is that those entries are required because ipv6
> doesn't support proxy ICMP ND.
>
> What does that mean in plain English?
>
> And, doesn't that negate the whole idea of using a default static
route?
>
> And, does this also mean that whenever a default static route is
> configured
> in ipv6, a static L3 to L2 map will be required for every ipv6
destination
> that needs to be reached or is there something in particular about
this
> scenario that makes this required?
>
> Besides running an ipv6 IGP between R4 and R6, is there any other
> alternative to having a static L3 to L2 map for each destination?
>
> Sorry for all the questions but I truly don't follow the logic at work
> here.
>
> TIA, Tim
>
>
This archive was generated by hypermail 2.1.4 : Wed Jul 06 2005 - 14:43:41 GMT-3