[c-nsp] New IPv6 BGP peer on a pure IPv4 network

Ziv Leyes zivl at gilat.net
Tue Dec 2 07:17:59 EST 2008

Well, when you say it,  it sounds very simple, the problem is I don't really know the subneting stuff for IPv6, for example.
We don't use any of the IGP you've mentioned in our IPv4 setup, we only have some iBGP  peers between our routers.
Do we HAVE to use OSPF, ISIS or EIGRP or we can still use only iBGP on IPv6 when needed? Remember I'm not moving the whole network to v6, only additional to the current v4.
Let's say I have a circuit connection to one uplink provider and I have a BGP peering between both sides on IPv4 /32 addresses, you suggest that I ask the provider to move to IPv6, what happens then to the whole IPv4 addresses? What happens to other devices that know this IPv4 address and won't know the new IPv6 address? What about the loopback IPs that are used for other peering and stuff?
Is there a way to transfer IPv4 traffic through an IPv6 BGP and vice versa?


-----Original Message-----
From: Gert Doering [mailto:gert at greenie.muc.de]
Sent: Tuesday, December 02, 2008 1:38 PM
To: Ziv Leyes
Cc: cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] New IPv6 BGP peer on a pure IPv4 network


On Tue, Dec 02, 2008 at 12:36:03PM +0200, Ziv Leyes wrote:
> I know this has probably been asked a thousand times. I'm not asking for answers, only for directions on where to start from.

Well, my standard answer to IPv6 is

  " there is nothing magic about it, just the addresses look funny "

so - you need

 - get addresses (from RIPE, very easy, just ask and receive a /32)

 - put IPv6 addresses on your router interconnections
   (/64 networks, pick whatever feels comfortable for the host part)

 - put IPv6 addresses (/128) on your router loopbacks
   (from a set-aside /64 for loopback addresses)

 - decide on an IGP (OSPFv3, ISIS, EIGRPv6), and turn it on
   - use whatever is most similar to the IPv4 IGP you're comfortable with

 - add "address-family ipv6" to your BGP configs, and add "network" and
   "neighbour" statements for iBGP and eBGP peers
   - follow the same rules you do for IPv4 BGP regarding ingress/egress
     filtering, BGP community settings, etc.

 - talk to your upstream providers, tell them you require IPv6, otherwise
   you'll have to change providers.

 - IOS 12.4 is fine for IPv6

 - the trick is: do not despair.  If you know your trade in IPv4, IPv6
   really is very similar - all the concepts (IGP, iBGP, eBGP, loopback
   addresses, ...) are the *same*.  Just funny-looking addresses.

 - of course there's lots of work in this.


PS: I'm happy to help on the mailing list, if you have specific questions - and I'm also earning a living by doing consulting work, if you do not want to have the questions and answers on the mailing list :-)

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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de

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