Category: MPLS
PCEP and BGP-LS Questions and Answers
Julien Lucek concluded his PCEP and BGP-LS webinar with a lengthy Q&A session addressing all sorts of questions from the audience (to access all videos in this webinar, register here).
PCEP Extensions
The moment an IETF working group agrees on a protocol someone starts creating extensions. PCEP is no exception; in the last part of the BGP-LS and PCEP webinar Julian Lucek talked about some of them.
PCEP Usage Scenarios
After covering the details of PCEP protocol in the BGP-LS and PCEP Deep Dive webinar Julian Lucek focused on how a controller would use PCEP to build MPLS TE paths across a network.
Oh, and don’t forget to explore the rest of the PCEP webinar and other SDN webinars after watching the video ;)
Zero Bandwidth Traffic Engineering
Oliver Steudler from Juniper sent me a link to an interesting Juniper blog post describing zero-bandwidth traffic engineering.
Read the blog post first and then come back for some opinionated rambling ;)
Is the problem real? Yes.
Video: PCEP Deep Dive
After explaining the basics of BGP-LS and PCEP, and a quick deep dive into BGP-LS, Julian Lucek focused on the second topic of his excellent webinar and described the details of Path Computation Element Protocol (PCEP).
Why Would You Need BGP-LS and PCEP?
My good friend Tiziano Tofoni (the organizer of wonderful autumn seminars in Rome) sent me these questions after attending the BGP-LS and PCEP Deep Dive webinar, starting with:
Are there real use cases for BGP-LS and PCEP? Are they really useful? Personally I do not think they will ever be used by ISP in their (large) networks.
There are some ISPs that actually care about the network utilization on their expensive long-distance links.
Introduction to BGP-LS and PCEP
Julian Lucek did a fantastic job describing how NorthStar controller uses BGP-LS and PCEP, so I asked him whether he’d be willing to do a deep dive on these two topics. He gracefully agreed, and the results are already online.
Optimizing Traffic Engineering with NorthStar Controller on Software Gone Wild
Content providers were using centralized traffic flow optimization together with MPLS TE for at least 15 years (some of them immediately after Cisco launched the early MPLS-TE implementation in their 12.0(5)T release), but it was always hard to push the results into the network devices.
PCEP and BGP-LS all changed that – they give you a standard mechanism to extract network topology and install end-to-end paths across the network, as Julian Lucek of Juniper Networks explained in Episode 43 of Software Gone Wild.
LDP Label Allocation Revisited
One of my readers was having an LDP argument with his colleague:
Yesterday I was arguing with someone who works for a large MPLS provider about LDP label allocation. He kept saying that LDP assigns a label to each next-hop, not to each prefix. Reading your blog, I believe this is the default behavior on Juniper but on Cisco LDP assigns a unique label for each IGP (non-BGP) prefix.
He’s absolutely right; Cisco and Juniper use different rules when allocating MPLS labels.
Combining MPLS/VPN, MPLS-TE and QoS on MPLS Talks
In the final part of our MPLS-focused discussion (now part of MPLS Essentials webinar), Seamus wanted to know how one could combine MPLS/VPN, MPLS-TE and QoS (for example, sending VoIP traffic for one customer over a different path).
Short answer: don’t even think about doing that. The added complexity is not worth whatever extra money you’ll be charging the customer (or not).
Tech Talks: Load Sharing and Entropy Labels in MPLS Networks
Load sharing in MPLS networks is always an interesting topic, and we couldn’t possibly avoid it during our MPLS-focused Tech Talks – watch the video.
After discussing the load sharing intricacies we briefly dabbled with the concept of entropy labels.
How Does MPLS-TE Interact with QoS
MPLS Traffic Engineer is sometimes promoted as a QoS solution (it seems bandwidth calendaring is a permanent obsession of some networking engineers, and OpenFlow is no more a solution than MPLS-TE was ;), but in reality it’s pretty hard to make the two work together seamlessly (just ask anyone who had to implement auto-bandwidth MPLS-TE in a large network).
Not surprisingly, we addressed the topic during our MPLS Tech Talk (now part of MPLS Essentials webinar).
MPLS Tech Talks: RSVP-TE 101
After discussing the basics of MPLS, MPLS-TE and LDP, and the relationship between FECs, LDP and BGP, Seamus and myself focused on another interesting topic: how MPLS protocol stack uses RSVP to implement traffic engineering.
MPLS P-Router, Router or Layer-3 Switch?
One of my readers is struggling with the aftermath of marketing gimmicks:
We will implement a new network soon, and we're discussing P-routers versus regular routers versus switches. I'm looking for arguments to go one way or the other.
Handling the Bottom of MPLS Stack
MPLS bottom-of-stack bit confused one of my readers. In particular, he had a problem with the part where the egress MPLS Label Switch Router (LSR) should go from labeled (MPLS) to unlabeled (IPv4, IPv6) packets and had to figure out what was in the packet.