2009.10.21 NANOG47 day 3 notes

And last, but not least, here's the notes from the morning
part of the NANOG meeting. I strongly, STRONLY suggest
people read Aaron's IPv6 deployment in a nutshell slides;
while I differ from him on some of the thoughts around address
allocation schemes for very large networks, for small to midsized
networks, it's a very, very good cookbook to follow for getting
IPv6 rolled out:


Thanks to everyone for participating, both locally and

subsequent ARIN notes will be posted to ppml list.


2009.10.21 NANOG47 Wednesday morning notes

Don't forget to fill out your survey!!

Dave Meyer welcomes everyone back from their
hangovers at 0904 hours Eastern Time.

John Curran isn't here, so he misses his 13
minutes of fame, and we go straight over to
Mark Kosters.

Mark Kosters, IPv6: Emerging stories of success.

A stellar panel of people to talk about
transitioning to v6.

IPv4 is running out; in 2 years or so, we'll
no longer have a flow of addresses from IANA
to the RIRs.
But why isn't more traffic moving onto IPv6,
given the imminent runout? Still less than
1% of the overall traffic.

What do you need to do to make the move to v6,
from the enterprise and ISP viewpoint?

John B, comcast
Matt R, ARIN
Owen DeLong, HE.net
Aaron Hughes, 6connect

John B from comcast is up first
Native, dual stack core and access networks

started as means to leverage device management;
then moved to subscriber access service.

Backoffice, where applicable, also dual stack
Cable modems (DOCSIS) single stack v4 or v6
eMTAs remain v4
eSTBs targeted to support v4 or v6 only
Native dual-stack subscriber services
Leverage well known transition technologies to enable
enterprise desktop IPv6 connectivity.

Some of the backoffice pieces, like DHCP, are
still evolving.
This is a team organizational effort, so it takes
many pieces working together.

Core concept--intial key piece was device management.
Core network, access network, and back office systems
all have to work together, or the program fails.
So, the iteratively extend those three elements to
offer services over IPv6

Native is preferred whenever possible over tunnels
and other techniques; but sometimes it's just not
possible. There's still much learning to happen
in the area to figure out how best to make the
deployment happen.

Lessons Learned
IPv6 must become business as usual for staff from
every area of business
lack of attention here be be problematic for v6 deployment
deferring or avoiding IPv6 will be problematic.

it's really, REALLY important to do large scale testing
of interoperability, especially when you have millions
of devices. You test the key interconnect points where
devices interact, especially with high levels of
diversity in your gear.
Also leverages technologies that newer releases, like
DOCSIS3.0 provide.
Find opportunties like that in your own environment.

Need to manage the deployment of v6 relative to other
business needs.
channel bonding vs v6, which gets business priority,
for example
Security on v6 is still a challenge
vendors often say "but you're the only one who has asked
for that"

backoffice and tool upgrades to support IPv6 are
best approach is to divide these efforts into smaller
Very substantial chunk of work; don't underestimate
  the challenges of this!

IPv6 data services for subscribers.
preferred approach is to offer native dual-stack v6
service to customers; v4 continues unchanged, just
adds v6.

Directly connected device that supports v6, or home
gateway device that supports v6.

all the support systems must support both models for
the rollout to work.

Most people in the room use a gateway device at home.

most home gateway devices don't support v6 yet,
so pushing the retail type devices to support v6
natively, off the shelf is a challenge.

Challenges associated with routing for delegated v6
prefixes should be uniformly addressed.

Support for v6 in many products is still considered
'new' and isn't as mature as v4.

testing and interoperability are critical for
successful deployment

bugs and issues will arise

scale makes a difference!

deploying IPv6 must not impact existing services
(this is pretty much true for everyone--can't break
existing customers!)

Content and Services
availability of content and services over IPv6 to date
appears to be lacking

simply having v6 connectivity isn't sufficient


Matt Ryanczak, network ops manager at ARIN
History of IPv6 @ARIN

They're a small, 50 person multihomed customer

Their network has been running IPv6 since 2003,
with a beta Sprint circuit.
it was a T1 line, appeared native, but was tunneled
inside Sprint.
v6 internet wasn't well connected.
2004 Worldcom circuit, similar issue.
Started connecting to exchange points, got transit
there, and is now starting to be able to serve large
volumes of traffic.

In 2003, T1 line from Sprint--very adhoc and beta,
used Linux Router, and OpenBSD firewall.
Completely segregated network. Not dual stack, too
many security issues at the time; was a bit afraid
of it at the time.
Path MTU discovery issues, packets just dying;
server MTU issues, upstream issues, great learning
process. Sprint circuit finally being decomm'd.
Sprint support was always really good.

2004, Worldcom circuit, part of Vint Cerf's test v6
network; real router this time, but OpenBSD firewall
still used. T1 into 2800 router. Duplicated the
services that were on Sprint link, provided a second
path to verify issues, see if the problem could be
duplicated or not.
Similar issues, PMTU discovery issues due to tunnels,
problems reaching chunks of Europe (problem for
serving DNS, for example)--good learning exercise.

2006, joined Equi6IX--beta at time, completely free,
100Mb ethernet, transit via OCCAID, things started
to look like production network; still had firewall,
same services, but the service level got a lot better,
still segregated network, but many routing issues
went away, PMTU issues started to disappear. started
to dual stack.

2008: NTT/TiNet IPv6;
built two networks, one west coast, one east coast,
would host all public services out there, separate
provisioning side from public side.
1000Mb links to NTT/TiNet using ASR 1000 routers
Foundry LBs, IPv6 support was Beta. They're very
responsive, been issuing patches for them.
Now it's a full dual-stack network end to end,
and Foundry is still working with them to figure
out how to best support the traffic.
Whois is out there, DNS out there, figuring out how
to expand the services.

Whois, about 0.12%
DNS about 0.55%
WWW IPv6 about 8% traffic in 2009
Most of that is internal ARIN traffic, since they're dual
stacked internally. :smiley:

Lessons learned
Tunnels are not desirable.
he.net tunnel at home is fine for home use, but using
them for production services, PathMTU discovery problems
are just a pain.

Not all transit is equal!

Routing is not as reliable as v4; people are still
learning, backbones aren't as good.

Dual stack isn't so bad, no security issues they're
aware of, stacks have gotten a lot better.

Proxies are good; use 6to4 proxies for current rwhois
servers, older routing registry (moving to v6 someday)

People fear 4byte ASN. They have people who can't
peer with them due to 4byte ASN. More people need to
get 4byte ASN code.

Native support is better.

DHCPv6 is not well supported. This really needs fixing.

Reverse DNS is a pain. No wildcards. Can't use same
tricks as v4, and is very error-prone.

Windows XP is broken but usable; can't do v6 DNS,
but mostly usable.

Bugging vendors does actually work. Helps if they
recognize your name (being ARIN doesn't hurt!)

Today and the Future
standardizing dual stack, ipv6 enabled by default,
including push scripts, back office, etc.
v6 support a requirement for vendors
All RFPs list IPv6 as a requirement

Be prepared to do a lot of work tweaking your back
office scripts!

Patrick, Akamai, -- do you do Google whitelist or do
you just break people who don't have v6 connectivity
to you who ask for AAAA records.
complaints. It does happen sometimes, but often they
can work with people to get them connected.

Kevin Oberman, ESnet
Recently, he had that issue, AAAA couldn't get there,
but he didn't open a ticket, he just went back to IPv4
make much money from website, so it's not as critical
for them as for some others, but they do work with
people to try to fix those cases.

Shift focus--what does it take to move enterprises
into v6?

Owen DeLong, what does it take to port systems from
v4 to v6?

Porting to Dual Stack -- not that hard

Why important? We've all seen the exhaustion point
code examples there

change variable names when changing types, to make
it easier to spot old variables.

sockaddr_in to sockaddr_in6
sockaddr_storage (generic storage type)
check address scoping (link local vs global, and
interface scope for link locals)

Some gotchas not in sample code
IP addresses in log files
IP addresses stored in databases
Parsing routines for external data

PERL porting example
refer to source code examples
v4_* are v4 only code

Add socket6 as well as socket module to code
replace get*byname calls
change protocol and address families in socket
and bind calls

get*byname to getaddinfo
If you pass in in6addr_any to getaddrinfo returns
localhost, not what you were looking for!

Example of actual old way getservbyname
becomes getaddrinfo

socket and bind calls, AF_INET6, not too bad

PERL client migrations, similar tactics
inet_ntoa to inet_ntop

now getaddrinfo simplifies DNS on client side

You can't cycle socket calls anymore for reads;
you have to explicitly create it each time right
now, as you don't know which family the previous
call was.

Handy function replacement slide from the
website, with structure replacement slide
owend at he dot net

Bill Fenner
some kernels have changed to only bind to v6
sockets when available; has he found that to
be the case?
what Owen has found is that on his boxes, it
binds to both.
Q: yes, some kernels behaved that way, which is
very unfortunate; there might be knobs that can
change the default behaviour.
with dual stack socket calls; get with him if you
have examples of bad kernels so he can post warnings.

Aaron Hughes, deploying dual stack on a network
succesful implementation requires good
supporting policies!

We need to participate in decisionmaking at the
company level, to determine when and how to deploy
v6. Timing will be different for different companies.

Dispel the myths
obtaining v6 addresses is hard
transit providers don't support it
no BGP multihoming

Obtaining IPv6 address space is not really hard.

My provider doesn't support v6!
right now, talk to others, you can get free transit.
he.net, wvfiber, probably others out there you can
talk to. This is really valuable to people right
Starting with IX locations--get IPv6 addresses from
your exchange point providers

Make a list of all relevant peering information
update peeringDB--let the rest of the world know
you have v6 addresses!

Follow your own company change processes for the

configure IPv6
locate existing v4 peering interfaces
enable v6 (cisco)
configure v6 address
ping some peers (look their IPs up in peeringDB)

within a minute, you can pass some ICMPv6 packets.

ipv6 unicast-routing
enabled by default

v4 and v6 are configured almost identically.

At this point, your IX interfaces are dual
stacked. :slight_smile:

Next up, the backbone.
Keeping track of peering interfaces in peeringDB
is great. For your backbone, you really want a
database to track them. Spreadsheets don't scale
terribly well. ^_^;
At least use a reverse DNS zone file

Come up with a good numbering plan for IPv6!!

If you take first /48 for infrastructure, take
first /64 for loopbacks,

You can take the opportunity to change your
architecture for v6 if you want, but it's easier
to keep is same as v4 so you don't have to keep
track of two topologies.

Architecture choices:
simple one:
loopbacks and connected infrastructure only in IGP
rest of stuff in BGP

Configure your backbone
Numbering plan?
IPv4 4th octet/32 -> IPv6 ::X/128

enable OSPFv3 if you're running OSPF:
ipv6 router ospf 12456
enable v6 on interface
configure OSPF for interface

do same thing on next router, verify the link is
up, reachable, and routed.

Managing assignments with DNS zone
you can just increment /48s in your zone file
don't forget that after 9 comes a!

It shouldn't take very long to do this, even
for a midsized network. It's tedious, but not

To reach the outside world, need some BGP
configure a new v6 peer group, you can mirror your
v4 peer group, but with route-maps and lists that
match v6 elements. Naming them -V6 makes it easier
to spot them later.

iBGP will be loopback to loopback, next-hop-self,
like with v4.

You can build a common config to be pushed out.

iBGP will handle connected interfaces (except

route-maps use slightly different syntax for
v6 matching:
match ipv6 address matchall

Don't panic when you do
address-family ipv6
it will reformat your config, your next Rancid run will
look scary, but it really didn't break your whole

You can build a common config chunk for all the IBGP
configs, and push it out.

Still doesn't let you reach outside world.

Next up, configure your external peers.

New peer group for v6 peers; you'll need new sanity
lists, there's not as many well-defined bogon filters;
but at least set filters on sizes
seq 5 permit ::/0 ge 16 le 48

Create a list of your ASNs IPv6 prefix(es) to allow out.

create route maps, use same communities and localprefs
to match what you use in v4

Next, send email to peering@he.net to get BGP up;
send the peering info file you collected early on.

Next up, turn up a peer with he.net, you'll see the
neighbor come up, and you can reach the world now. :smiley:

show bgp ipv6 unicast summary
show bgp ipv6 unicast neighbor X::Y adv

make sure you're sending and receiving the expected
routes; do some traceroutes and pings, make sure it
looks good.

Go ahead and continue turning up more peers.

Attaching a host to the v6 network.
use a *nonproduction* host to test with first!
Find a lab box, look at v4 routing and config;
allocate a /64 from your DNS zone file
(figure out your regional aggregation at some point)

Configure interface facing host, and depending on
the OS version, it may autoconfigure itself.

No more ARP, you can try to ping, you can look
at the neighbor table to see if your host is

Check your iBGP, see if you see the subnet in
your table now (first connected non-IGP subnet)

look at http://ripe.net/ to see if you get there
via v6 or not.

Note about SLAAC--the moment you configure the
interface on your router, *every* host on the
subnet can get a v6 address! Make SURE you have
your security concerns squared away before you
do this!

Time to add nameservice
reverse...is ugly. Look at the slide.
ns0 IN AAAA blech

reload nameserver

Note that your machine is now on the global v6
internet with every port open; in fact, every
host on that subnet is now on the global v6
internet. you MUST make sure your security
policy is ready to handle IPv6 security similar
to IPv4!

Peering--just about everyone out there will peer
via v6 at the moment; it's the right time to
dive in and make it happen.

Start working with a good beta customer to start
developing customer route maps, customer neighbor
configs (most of which will be mirrors of your v4
configs and route maps, but with different address
families and different filters)

Most networks are allowing multihoming of /48s at
this point, so you can let your downstream customer
know it's OK for them to announce the /48 to their
other upstream as well.

Step 1 is pretty easy; the network side isn't that

Step 2, getting hosts and content up and running
with security policy in place, operations staff
comfortable on IPv6, etc is the harder part.

So, on the network side, getting IPv6 up and
running isn't hard; it's very, very similar to v4.

Leo Bicknell--thanks for a great presentation,
good summary. Few small items.
BGP change on IOS, it does reformat things;
there is a command "bgp upgrade-cli" will change
your config to new format ahead of time to let
you check the delta ahead of time.
Presentation is heavy on IOS classic configs.
IOS-xr and JunOS allows for common policies
for both, with different lines and different
terms for v4 and v6; makes configs even simpler.
Lastly, with IPv6 reverse, people forget that
$ORIGIN exists, so you can make the zone files
look considerably easier to read.
Humans seem to work better when v6 host address
and v4 address map to each other statically,
rather than using SLAAC and having hosts
change when NICs change.
is very very good information to know.

Arjin, AMS-IX, since autoconfig is on by default,
might want to turn them off on exchange point

Cathy says this looks like the beginnings of
a WONDERFUL best current practices document;
let's turn it into one!

Next up is Betty with some results for us from
the elections.

196 people voted
Steve Feldman, Sylvie LaPierre, and
Duane Wessels are new SC members.

Austin, Texas, NANOG 48, see you Feb 21-24 2010.

Thanks to ARIN, Arbor, and Merit for this meeting!

There's new SC members; we're at the first point
since the restructuring where people have hit
term limits.

Josh, Joel, Ren, Todd, have been serving since the
revolution, and are aging out--a big round of applause
for them as well.


John Curran notes there is a break, and ARIN will start
at 11am. :slight_smile: