Diptanshu Singh
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Diptanshu Singh
Average Network Delay and Queuing Theory basics
So recently I was looking at the Linear programming formulations of Traffic engineering problems and one of the problem was to find the path with the goal to minimize the Average network delay. Which got me thinking that for topology design related problems, how can I calculate the Average network delay? As you can guess, […]Disjoint Path Routing and LP
We are all well aware about the problem space of finding the Shortest Path and use of Dijsktra algorithm. In this blog, we will take a peek at the problem space for Disjoint Path routing, see how it can be reduced to the optimization problem and a few algorithms in that space. So first, let’s […]Yet Another blog about Segment Routing -Part2 : TI-LFA
So finally got some time after a while to write something. In this post we will be looking at Topology Independent LFA aka TI-LFA. We will also compare TI-LFA with LFA, rLFA and TE-FRR. If you don’t already have familiarity with LFA’s or TE-FRR then take a look at my previous posts on TE design […]
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The post Yet Another blog about Segment Routing -Part2 : TI-LFA appeared first on Packet Pushers Podcast and was written by Diptanshu Singh.
BGP AIGP
In this post we will look at something which is relatively new but not as cool as my previous post on Segment Routing. We will take a look at a new BGP feature called “Accumulated IGP, metric of path to prefix” (RFC 7311 AIGP) which is an optional non-transitive attribute . A new AIGP TLV was created for this which contains […]
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The post BGP AIGP appeared first on Packet Pushers Podcast and was written by Diptanshu Singh.
Yet another blog about Segment Routing-Part 1
In this blog post we will be taking a deeper look at Node/Prefix SID and SR/LDP Interworking. If you work or have an interest in the Routing area, then by this time you may have already heard about Segment Routing (SR) and I am assuming that you already have some awareness with the basic concepts of […]
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The post Yet another blog about Segment Routing-Part 1 appeared first on Packet Pushers Podcast and was written by Diptanshu Singh.
BGP RR Design – Part 2
This is a continuation from Part 1 9. ACME VPN RR’s Design: So the current total number of PE’s dedicated for VPN functionality is around 400 (2 PE’s in each POP x 200). A full iBGP mesh between 400 PE’s comes around 79,800 sessions ((400×399) /2). By introducing two VPN RR’s each PE will have only two iBGP sessions […]
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The post BGP RR Design – Part 2 appeared first on Packet Pushers Podcast and was written by Diptanshu Singh.
BGP RR Design – Part 1
1. Introduction In this post we will be looking at large scale RR design by using a fictional ISP ACME as a reference. As usual, I am assuming that the reader has familiarity with BGP and basic RR concepts. 2. Setting the Stage ACME is a communications company providing communications and data services to residential, business, governmental and wholesale customers. […]
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The post BGP RR Design – Part 1 appeared first on Packet Pushers Podcast and was written by Diptanshu Singh.
IP FRR and Micro-loops Part 2
This is a continuation from Part 1 Remote LFA At this point we already know that simple LFA doesn’t always provide full coverage and its very topology dependent. Reason is simple i.e.in many cases backup next hop best path goes through the router calculating the backup next hop. This problem can be solved if we […]
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The post IP FRR and Micro-loops Part 2 appeared first on Packet Pushers Podcast and was written by Diptanshu Singh.
IP FRR and Micro-loops Part 1
Introduction In this post we will take a look at IP FRR and Micro-loops. If the reader already doesn’t have some kind of basic familiarity with IP FRR and Micro-loops, then I would highly recommend the reader go through below post series by Russ as he introduces various concepts in a very clear way. This post […]
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The post IP FRR and Micro-loops Part 1 appeared first on Packet Pushers Podcast and was written by Diptanshu Singh.
MPLS TE Design -Part 3
This is a continuation from Part 2 Fast Reroute Why Fast Reroute? Many NSP’s like ACME have traffic with tight SLAs. For instance below is an ITU delay recommendation for Voice. One Way Delay Characterization of Quality 0-150ms Acceptable for most applications 150-400ms May impact some applications Above 400ms Unacceptable ITU G.114 delay recommendations Having […]
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The post MPLS TE Design -Part 3 appeared first on Packet Pushers Podcast and was written by Diptanshu Singh.
MPLS TE Design -Part 2
This is a continuation from Part 1 Case for LDPoRSVP As we mentioned at the very beginning that ACME provides L3VPN and L2VPN services, which requires end to end LSP between the PEs. But due to scaling reasons, ACME decided not to extend RSVP to the edge routers. This creates a problem as there is […]
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The post MPLS TE Design -Part 2 appeared first on Packet Pushers Podcast and was written by Diptanshu Singh.
MPLS TE Design -Part 1
In this post we will be exploring different aspects of Traffic Engineering (RSVP-TE) from a design perspective using fictional ISP as a reference. The intent of the post is to not necessarily recommend a particular solution, but to bring up different aspects involved in the design. I am assuming that the reader already has somewhat […]
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The post MPLS TE Design -Part 1 appeared first on Packet Pushers Podcast and was written by Diptanshu Singh.
NG mVPN-Control Plane Overview
In this post we will be exploring the shortcomings of MVPN (Draft Rosen/RFC 6037), with a focus on how NG-MVPN technologies address these limitations. Why NG-MVPN? The base specification for BGP/MPLS VPNs, RFC4364, only addresses unicast, and the first proposal for multicast support in BGP/MPLS VPNs is often known as Draft Rosen (which is now […]
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The post NG mVPN-Control Plane Overview appeared first on Packet Pushers Podcast and was written by Diptanshu Singh.
EVPN: Intro to next gen L2VPN
Introduction: With the ascent of DCI, a new set of requirements emerged which are not fully addressed by current L2VPN technologies like VPLS. There are three major options in deploying VPLS LDP based VPLS (RFC 4762) LDP based VPLS with BGP Auto discovery BGP based VPLS (RFC 4761) Each option has its pros and cons. […]
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The post EVPN: Intro to next gen L2VPN appeared first on Packet Pushers Podcast and was written by Diptanshu Singh.