BGP performance tuning – Convergence, Stability, Scalability and NSF (Part 3)

Lets continue our BGP performance tuning discussion. Sorry for the long delay but I was deeply busy in some other stuff. During the last couple of days I’ve attended Cisco Expo 2009, and during the SP – IP Core Technical Breakout, the breakout speaker highlighted Cisco’s high availability features, while focusing on BGP he introduced to my knowledge a new BGP feature that I found attractive, BGP PIC (Prefix-Independent Convergence) Core/Edge – Currently only available with Cisco IOS-XR for Cisco CRS-1, Cisco XR 12000 and the new Cisco ASR 9000 routers series, I should be covering this feature later.

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WISB Free Telnet Tool

WISB is our first free application to the networkers community. The application is used to simplify mass configuration tasks on multiple devices, by automating the telnet connectivity and applying the configuration provided in the configuration files. Currently it is supporting IOS devices only. After stabilizing this beta version we are going to support other devices and implement some other features. some of the benefits you can get from such tool are: Loading initial configuration/backup configuration files for your study Labs. Apply configuration to a list of network devices at once. “i.e. change username/password, SNMP, logging configuration…etc.”. This is very useful …

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What is LDP extended discovery?

Normally LDP neighbors are found automatically by sending UDP Hello packets on Port 646 with the destination of multicast address 224.0.0.2 out of each LDP enabled interface. In some MPLS applications a LDP session must be established between non directly connected peers to exchange labels. In such cases Hello packets can not be just broadcasted, instead these Hello packets are sent as unicast packets using UDP on port 646 and destined to the targeted peer. AToM and some Traffic Engineering scenarios are examples of these applications that require a targeted LDP session between non directly connected routers.

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Draft Martini, Draft Kompella and L2VPN services

Draft Martini and Draft Kompella were the starting points toward standardizing the Layer2 VPN architectures using pseudowire emulation, both drafts addressed setting up pseudowire emulation over MPLS-based networks in order to offer Layer 2 VPN services, but each draft proposed a different approach. Members of the networking community divided themselves into two camps based on the different design philosophies that were embedded in the two drafts. This resulted in many drafts and debates until things converged time by time. I’ll try to simply describe both drafts, and how things eventually went out.

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MPLS Special Labels

MPLS label range from 0 to 1,048,575 (configurable on Cisco IOS) Labels 0 through 15 are reserved labels. An LSR cannot use them in the normal case for forwarding packets, the labels from 16 through 1,048,575 are used for normal packet forwarding. In Cisco IOS, the default range is 16 through 100,000. This number is more than enough for labeling all the IGP prefixes in large routing table, but in very large scale networks this number might be insufficient, so we can change the label range with the mpls label range min max command LSR1(config)#mpls label range ? <16-1048575>  Minimum …

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Static Routes Label Binding

In this post we will be discussing the label binding for static routes and the forwarding of labeled packets destined to these destinations. IP routing protocols build the IP routing table, and each LSR assigns a label to every destination in its IP routing table independently (Independent LSP Control – Connected, static or learned dynamically via IGP) , afterwards the LSRs announce their assigned labels to all other LSRs (Unsolicited Downstream Label Distribution), then every LSR receives the label binding information from the downstream LSRs and store it in the LIB table (Liberal Label Retention Mode), then each LSR picks …

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