Aug
17
Edit: For those of you that want to take a look first-hand at these packets, the Wireshark PCAP files referenced in this post can be found here One of the hottest topics in networking today is Data Center Virtualized Workload Mobility (VWM). For those of you that have been hiding under a rock for the past few years, workload mobility basically means the ability to dynamically and seamlessly reassign hardware resources to virtualized machines, often between physically disparate locations, while... Read More
May
10
Update: Congrats to Mark, our winner of 100 rack rental tokens for the first correct answer, that XR2 is missing a BGP router-id.  In regular IOS, a router-id is chosen based on the highest Loopback interface.  If there is no Loopback interface the highest IP address of all up/up interfaces is chosen.  In the case of IOS XR however, the router-id will not be chosen from a physical link.  It will only be chosen from the highest Loopback interface, or from the manual router-id command.  Per the... Read More
Oct
28
INE's long awaited CCIE Service Provider Advanced Technologies Class is now available! But first, congratulations to Tedhi Achdiana who just passed the CCIE Service Provider Lab Exam! Here's what Tedhi had to say about his preparation: Finally i passed my CCIE Service Provider Lab exam in Hongkong on Oct, 17 2011. I used your CCIE Service Provider Printed Materials Bundle. This product makes me deep understand how the Service Provider technology works, so it doesn`t matter when Cisco has... Read More
Oct
18
One of our most anticipated products of the year - INE's CCIE Service Provider v3.0 Advanced Technologies Class - is now complete!  The videos from class are in the final stages of post production and will be available for streaming and download access later this week.  Download access can be purchased here for $299.  Streaming access is available for All Access Pass subscribers for as low as $65/month!  AAP members can additionally upgrade to the download version for $149. Read More
Aug
30
One of the frequent questions I hear regarding L3VPNs, is regarding the bottom VPN label.  In this article, we will focus on the control plane that provides both the VPN and transit labels, and then look at the data plane that results because of those labels. In the topology, there are 2 customer sites (bottom right, and bottom left).  The BGP, VRFs, Redistribution, etc are all configured to allow us to focus on the control and data plane.   Lets begin by verifying that R1 is sourcing the... Read More
Aug
26
In this blog post we’re going to discuss the fundamental logic of how MPLS tunnels allow applications such as L2VPN & L3VPN to work, and how MPLS tunnels enable Service Providers to run what is known as the “BGP Free Core”. In a nutshell, MPLS tunnels allow traffic to transit over devices that have no knowledge of the traffic’s final destination, similar to how GRE tunnels and site-to-site IPsec VPN tunnels work. To accomplish this, MPLS tunnels use a combination of IGP learned information, BGP... Read More
Aug
16
Abstract In this blog post we are going to review a number of MPLS scaling techniques. Theoretically, the main factors that limit MPLS network growth are: IGP Scaling. Route Summarization, which is the core procedure for scaling of all commonly used IGPs does not work well with MPLS LSPs. We’ll discuss the reasons for this and see what solutions are available to deploy MPLS in presence of IGP route summarization. Forwarding State growth. Deploying MPLE TE may be challenging in large network as... Read More
Aug
16
Last week we wrapped up the MPLS bootcamp, and it was a blast!   A big shout out to all the students who attended,  as well as to many of the INE staff who stopped by (you know who you are :)).    Thank you all. Here is the topology we used for the class, as we built the network, step by step. The class was organized and delivered in 30 specific lessons. Here is the "overview" slide from class: Read More
Jul
19
Can you solve this puzzle? R2, R3 and R4 create the service provider network, with MPLS on all three routers, and iBGP at the PE routers.  R1 and R5 are the CE routers. R2, prefers the BGP next hop of 4.4.4.4 for network 5.5.5.5 (R5 loopback). R4, at 4.4.4.4 is an iBGP neighbor. R2#show ip route vrf v | inc 5.5.5.0 B 5.5.5.0 [200/409600] via 4.4.4.4, 00:06:47 Is R2 preferring an iBGP learned route, which has an AD of 200, over a EIGRP route, which would have an AD of 90? Can you identify why... Read More
Jun
28
In the previous MPLS Components post, we discussed the many benefits that MPLS can bring to the network, and we detailed the typical components found in a Layer 3 MPLS VPN design. In this post, we will provide more details for the MPLS components and their important, inner workings. We will make reference to the previous diagram in this post as well: When PE1 receives a packet from CE1, it will engage in what we call a Push operation. PE1 is considered the ingress PE router and engages in label... Read More

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