MicroNugget: What is IPv6 PreFix Delegation?

[@vladislavkaras491]

I could not find a better video about how ISPs allocate their IPv6 and how local devices gets an actual GUA IPv6 address. Thanks for the video!

[@KeithBarker]

Hi Russdog- The global unicast address range begins with 2000 through 3fff (inclusive). The reason for that is that the specification for the global unicast address is 2000::/3 (so there is an example of the /3). Each of the characters in 2000 are Hex, and really represent 4 bits. In binary, the 2000 would look like this: 0010 0000 0000 0000 The /3 means only pay attention to the first 3 bits, leaving us with 0010 (2) or 0011 (3) as the first character. Hope that helps, Keith

[@KeithBarker]

Hi Russdog- In the demonstration, I didn't use the command "address prefix 200...." to assign IP addresses for this pool to hand out, I only configure the DHCP pool for prefix delegation. The command: "show ipv6 local pool" should show the network block from which PD is occuring. If you follow the example in the video, and do the show command at about the 4 minute mark, are you getting different results than shown in the video? Keith

[@e9g9g]

Thanks for having such a detailed video. It helped me way more than the Cisco site's tutorials did.

[@MystikIncarnate]

Thank you very much Keith, you're my hero. I love these straight forward tutorials. off to my lab to do some testing!!

[@mattwilson1669]

Thanks Keith, great MicroNugget. If the link between PE & CE goes down, all the global unicast addresses on all interfaces on the CE router are lost. Is this the case? How would that affect the internal network WRT routing, as all the internal IPv6 addresses would only be link-local ones which aren't routable?

[@KingGrio]

Thanks, clear and to the point

[@aamirsadiq]

HI Keith, i wish you could demo how to add a DHCPv6 relay agent in the same mix

[@Aghabalayev]

Thanks a lot Keith. I love your lessons very much!

[@serggarcia3467]

Outstanding info! So, for a home network, our router configuration should have prefix delegation selected, correct?

[@KeithBarker]

What IOS version are you using?

[@dumbledor123]

This is a great video if you need to know how to setup your router at home. Thank you!

[@2007Russdog]

I saw a question on the ICND2 test practice that had an IPV6 address with a /3 on the end! What would that mean?

[@BoiseTriathlete]

Hi Keith - I am working my way through your IPv6 course, and I have a bit of a PD misunderstanding. I wanted to vary your example (to reinforce IPv6 subnetting for me). In my implementation, I wanted R4 (the ISP) to have a /50 prefix pool which would be carved up into /61 subnets for customers (11 bits so I could have 2048 such subnets to hand out). When I tell R4 to use a local pool of 2001:db8:2:c::/50 61, the IOS ignores that I specified the "c" and instead shows the prefix of 2001:db8:2::/50. If my math is right, 2001:db8:2:c::/50 is a different subnet than 2001:db8:2:0::/50. Why is the IOS ignoring my "C"? I am trying to set the 49th and 50th bit to be 1 in binary, hence the hex of C (but I am sure you picked up on that).

[@BoiseTriathlete]

I just figured out my own problem - stupid me! I cannot drop the trailing 0's in the "C" hextet. Local pool of 2001:db8:2:c000::/50 worked fine. I should have known better :-) Really enjoying your course, Keith.

[@2007Russdog]

When I configure the first router.. When i type Show IPV6 DHCP pool it doesnt show anything except the CUST-POOL. And no address ranges.

[@2007Russdog]

When I do the "Show ipv6 local pool" I get nothing displayed

[@Mi_Fa_Volare]

Your tone reminds me of LinusTechtips.

[@cbtnuggets]

Could you be a little more specific? What are you having trouble with?

[@2007Russdog]

I can't get this to work. Hmmm.

[@ziedsassi5722]

you're beautiful man :)

[@vijgai3]

Please slow down a bit while talking and typing. Other than that all good.

[@cbtnuggets]

Thank you for your feedback, Vijay!

[@tahersadeghi6773]

It looks like you are repeating to yourself rather than teaching. You talk too fast and type too fast and then say it was so easy!