Posts Tagged ‘CCDP’
In our CCDP bootcamp, we examined Cisco’s implementation of Virtual Private LAN Services (VPLS) in some detail. One blog that I promised our students was more information about how large enterprises or Internet Service Providers can enhance the scalbility of this solution.
First, let us review the issues that influence its scalability. We covered these in the course, but they are certainly worth repeating here.
Remember that VPLS looks just like an Ethernet switch to the customers. As such, this solution can suffer from the same issues that could hinder a Layer 2 core infrastructure. These are:
- Control-plane scalability – classic VPLS calls for a full-mesh of pseudo-wires connecting the edge sites. This certainly does not scale as the number of edge sites grow – from both operational and control-plane viewpoints.
- Network stability as the network grows – Spanning Tree Protocol-based (STP) infrastructures tend not to scale as well as Multiprotocol Label Switching (MPLS) solutions.
- Ability to recover from outages – as the VPLS network grows, it could become much more susceptible to major issues for customer connectivity in the result of a failure.
- Multicast and broadcast radiation to all sites – remembering that the VPLS network acts as a Layer 2 switch reminds us that multicast and broadcast traffic can be flooded to all customers across the network.
- Multicast scalability – multicast traffic has to be replicated on ingress PE devices, which significantly reduces forwarding efficiency.
- IGP peering scalability issues – all routers attached to the cloud tend to be in the same broadcast domain and thus IGP peer, which results in full-mesh of adjacencies and excessive flooding when using link-state routing protocols.
- STP loops – it is certainly possible that a customer creating an STP loop could impact other customers of the ISP. STP may be blocked across the MPLS cloud, but it is normally used for multi-homed deployments to prevent forwarding loops.
- Load-balancing – the use of MPLS encapsulation hides the VPLS encapsulated flows from the core network and thus prevents the effective use of ECMP flow-based load-balancing.
BGP (see ) is the de-facto protocol used for Inter-AS connectivity nowadays. Even though it is commonly accepted that BGP protocol design is far from being ideal and there have been attempts to develop a better replacement for BGP, none of them has been successful. To further add to BGP’s widespread adoption, MP-BGP extension allows BGP transporting almost any kind of control-plane information, e.g. to providing auto-discovery functions or control-plane interworking for MPLS/BGP VPNs. However, despite BGP’s success, the problems with the protocol design did not disappear. One of them is slow convergence, which is a serious limiting factor for many modern applications. In this publication, we are going to discuss some techniques that could be used to improve BGP convergence for Intra-AS deployments.
BGP-Only Convergence Process
Tuning BGP Transport
BGP Fast Peering Session Deactivation
BGP and IGP Interaction
BGP PIC and Multiple-Path Propagation
Practical Scenario: BGP PIC + BGP NHT
Considerations for Implementing BGP PIC
Appendix: Practical Scenario Baseline Configuration
Cisco originally promised us a new CCDP exam (version 2.1) on Nov 8, 2010.
That date is now moved to December 23, 2010. Our Class On Demand was designed to cover you for the old blueprint and the new, so there should be no concern for students. Of course we will be taking the new exam the week following its release and we will be sure to provide any updates to the course that may be required free of charge.
In the meantime, watch blog.ine.com for many posts regarding valuable extra technical information regarding this popular new course. I also want to send out one more thank you to the many students we had that were active participants in the live event. It was an honor to have so many Cisco employees join us, as well as the many highly motivated students from around the world.
Here is the recommended reading list that several asked for from our CCDP Bootcamp. Thanks again to all that attended for the awesome participation and discussions.
The INE CCDP Bootcamp covers in depth information about the Nexus line from Cisco Systems. Here is some of the overview information from the course for those that desire a quick introduction to this line of equipment.
With the Nexus gear, Cisco introduces us to yet another operating system called NX-OS. The platforms that run this Operating System include:
- Nexus 7000
- Nexus 5000
- Nexus 2000
- Nexus 1000V
- Cisco MDS 9000
- Cisco Unified Computing System (UCS)
- Nexus 4000
What are the key features of this new Operating System? Capabilities include:
- Virtual Device Contexts (VDC) – devices can be segmented into virtual devices
- Virtual Port Channels (vPC) – switches or servers able to use EtherChannel across two upstream switches
- Continuos system operation – thanks to features like In-Service Software Upgrade (ISSU) and dynamic restart for processes
- Security – 802.1AE
- From Base Service licenses to Advanced Services and Transport Services
Just a quick reminder that the CCDA and CCDP exams are updating to version 2.1 on November 8, 2010.
Our upcoming CCDP Bootcamp will reflect the new 2.1 exam, and we will be updating our CCDA Bootcamp in November/December 2010 as well. As always, customers that had previously purchased the CCDA Bootcamp will receive the updates free of charge.
Thank you so much for choosing INE, and enjoy your studies!