Showing posts with label Service Providers. Show all posts
Showing posts with label Service Providers. Show all posts

Don’t Use ULA Addresses in Service Provider Core

Dan sent me the following question:

I had another read of the ‘Building IPv6 Service Provider Networks’ material and can see the PE routers use site local ipv6 addressing. I’m about to build another small service provider setup and wondered: would you actually use site local for PE loopbacks etc, or would you use ULA or global addressing? I’m thinking ULA would be better from a security point of view?

TR&DR summary: Don’t do that.

Deutsche Telekom TeraStream: Designed for Simplicity

Almost a year ago rumors started circulating about a Deutsche Telekom pilot network utilizing some crazy new optic technology. In spring I’ve heard about them using NFV and Tail-f NCS for service provisioning … but it took a few more months till we got the first glimpses into their architecture.

TL&DR summary: Good design always beats bleeding-edge technologies

MPLS/VPN Carrier’s Carrier – Myth or Reality?

Andrew is struggling with MPLS/VPN providers and sent me the following question:

Is "carriers carrier" a real service? I'm having a bit of an issue at the moment with too many MPLS providers […] Carrier’s carrier would be an answer to many of them, but none of the carriers admit to being able to do this, so I was wondering if it's simply that I'm speaking to the wrong people, or whether they really don't...

Short answer: I have yet to see this particular unicorn roaming the meadows of reality.

Juniper MX Routers – all you ever wanted to know

During a recent ExpertExpress engagement I got an interesting question: “could we do per-customer policing and shaping on an MX-80 if we want to offer VPLS services and have Q-in-Q encapsulation on customer-facing links?” As I have preciously little Junos/MX knowledge, it was time for the classic “I’ll get back to you” reply and some heavy research.

You probably know how hard it is to find in-depth information on an unknown platform running unfamiliar software. Fortunately, Doug Hanks (@douglashanksjr) sent me a review copy of his new Juniper MX Series book a while ago. It was time for some serious reading.

The best of RIPE65

Last week I had the privilege of attending RIPE65, meeting a bunch of extremely bright SP engineers, and listening to a few fantastic presentations (full meeting report @ RIPE65 web site).

I knew Geoff Huston would have a great presentation, but his QoS presentation was even better than I expected. I don’t necessarily agree with everything he said, but every vendor peddling QoS should be forced to listen to his explanation of the underlying problems and kludgy solutions first.

IPv6 over PPPoE works great with IOS XE 3.7

Beatrice Ghorra (@beebux) was kind enough to share the results of her IPv6-over-PPPoE tests with me.

Short summary: everything works as expected on ASR 1K running IOS XE 3.7.

The Difference between Metro Ethernet and Stretched Data Center Subnets

Every time I rant about large-scale bridging and stretched L2 subnets, someone inevitably points out that Carrier (or Metro) Ethernet works perfectly fine using the same technologies and principles.

I won’t spend any time on the “perfectly fine” part (Greg Ferro had a lot to say about that in the early Packet Pushers podcasts), but focus on the fundamental difference between the two: the use case.

Do we need DHCPv6 Relay Redundancy?

Instead of drinking beer and lab-testing vodka during the PLNOG party I enjoyed DHCPv6 discussions with Tomasz Mrugalski, the “master-of-last-resort” for the ISC’s DHCPv6 server. I mentioned my favorite DHCPv6 relay problem (relay redundancy) and while we immediately agreed I’m right (from the academic perspective), he brought up an interesting question – is this really an operational problem?

Prefix-Independent Convergence (PIC): Fixing the FIB bottleneck

Did you rush to try OSPF Loop Free Alternate on a Cisco 7200 after reading my LFA blog post ... and disappointedly discovered that it only works on Cisco 7600? The reason is simple: while LFA does add feasible-successor-like behavior to OSPF, its primary mission is to improve RIB-to-FIB convergence time.

IPv6 End User Authentication on Metro Ethernet

One of the areas where IPv6 sorely lacks feature parity with IPv4 is user authentication and source IP spoofing prevention in large-scale Carrier Ethernet networks. Metro Ethernet switches from numerous vendors offer all the IPv4 features a service provider needs to build a secure and reliable access network where the users can’t intercept other users’ traffic or spoof source IP addresses, and where it’s always possible to identify the end customer from an IPv4 address – a mandatory requirement in many countries. Unfortunately, you won’t find most of these features in those few Metro Ethernet switches that support IPv6.

Source MAC address spoofing DoS attack

The flooding attacks (or mishaps) on large layer-2 networks are well known and there are ample means to protect the network against them, for example storm control available on Cisco’s switches. Now imagine you change the source MAC address of every packet sent to a perfectly valid unicast destination.

Building CsC-enabled MPLS backbone

Just got this question from one of my Service Provider friends: “If I am building a new MPLS backbone from scratch, should I design it with Carriers Carrier in mind?” Of course you should ... after all, the CsC functionality has almost no impact on the MPLS backbone (apart from introducing an extra label in the label stack).

Ensuring multi-tenant security in cloud services

One of the interesting problems I was facing in the recent weeks was multi-tenant security. Combine it with fuzzy all-encompassing vapor-based terminology and you have a perfect mix that can fit anything you want to sell. In the Ensuring multi-tenant security in cloud services I wrote for I tried to structure the cloudy visions a bit: let’s figure out which type of service we’re talking about, then we can discuss what security mechanisms make sense.

As you might expect, I find IaaS the most challenging as you’re bound to hit a number of roadblocks, from VLAN limitations to architectural limitations of virtual security appliances.

Read more @ SearchTelecom ...

Framed-IPv6-Prefix used as delegated DHCPv6 prefix

Chris Pollock from io Networks was kind enough to share yet another method of implementing DHCPv6 prefix delegation on PPP interfaces in his comment to my DHCPv6-RADIUS integration: the Cisco way blog post: if you tell the router not to use the Framed-IPv6-Prefix passed from RADIUS in the list of prefixes advertised in RA messages with the no ipv6 nd prefix framed-ipv6-prefix interface configuration command, the router uses the prefix sent from the RADIUS server as delegated prefix.

This setup works reliably in IOS release 15.0M. 12.2SRE3 (running on a 7206) includes the framed-IPv6-prefix in RA advertisements and DHCPv6 IA_PD reply, totally confusing the CPE.

Building IPv6 SP Core webinar - last session in 1H2011

As expected, the demand for the Building IPv6 Core webinar is slowly diminishing – those ISPs that know what IPv6 is all about are already implementing it. The session on March 10th is thus the last live session in the first half of 2011; if you’d like to attend a live session, now is the time to register for it.

Please note that the webinar is not going away: you’ll still be able to buy the webinar recording or watch the recordings as part of the yearly subscription package.

Delegated IPv6 prefixes – RADIUS configuration

Last week I described how Cisco IOS uses two RADIUS requests to authenticate an IPv6 user (request#1) and get the delegated prefix (request#2). The second request is sent with a modified username (-dhcpv6 is appended to the original username) and an empty password (the fact that is conveniently glossed over in all Cisco documentation I found).

FreeRADIUS server is smart enough to bark at an empty password, to force the RADIUS server to accept a username with no password you have to use Auth-Type := Accept:

Site-A-dhcpv6   Auth-Type := Accept
        cisco-avpair = "ipv6:prefix#1=fec0:1:2400:1100::/56"


Last week I got an interesting tweet: “Hey @ioshints can you tell me what is the radius parameter to send ipv6 dns servers at pppoe negotiation?” It turned out that the writer wanted to propagate IPv6 DNS server address with IPv6CP, which doesn’t work. Contrary to IPCP, IPv6CP provides just the bare acknowledgement that the two nodes are willing to use IPv6. All other parameters have to be negotiated with DHCPv6 or ICMPv6 (RA/SLAAC).

The following table compares the capabilities of IPCP with those offered by a combination of DHCPv6, SLAAC and RA (IPv6CP is totally useless as a host parameter negotiation tool):

PPPoE testbed, part 2

During my last Building IPv6 Service Provider Core webinar (register here) I got a lot of questions about IPv6 over PPPoE (obviously we’re close to widespread IPv6 implementation; I never got PPPoE questions before). I wanted to test various scenarios in my IPv6 lab and thus enabled PPPoE on an Ethernet link between CE and PE routers using the configurations I published last year.

This time I wanted to test multiple configurations in parallel ... no problem thanks versatile PPPoE implementation in Cisco.

IPv6 SP Core webinar: router configurations

The attendees of my Building IPv6 Service Provider Core webinar (register here) get several sets of complete router configurations for a six router lab that emulates a typical Service Provider network with a residential customer and an enterprise BGP customer. The configurations can be used on any hardware (real or otherwise) supporting recent Cisco IOS software, allowing you to test and modify the design scenarios discussed in the webinar.

Deploying IPv6 article @ SearchTelecom

Following my Transition to IPv6” articles, Jessica Scarpati from wrote a series of articles covering the telecom transition plans and the problems they’re experiencing with the vendors and content providers.

In the second article of the series, “Deploying IPv6? Demand responsiveness from vendors, content providers”, she’s quoting John Jason Brzozowski from Comcast, John Curran from ARIN, Matt Sewell from Global Crossing and myself. My key message: vote with your money and take your business elsewhere if the vendors don’t get their act together.