In the previous post on MSS, MSS Clamping, PMTUD, and MTU, we learned how PMTUD is performed by setting the Don’t fragment flag in the IP header which leads to the device that needs to perform fragmentation dropping the packet
VRF Without Route Target – Will the Route Be Exported?
Yesterday I posted a tricky question to Twitter. If you have a working VPNv4 environment and create a VRF with only a Route Distinguisher (RD) but without Route Targets (RT), will the route be exported? The answer may surprise you!
CCDE – Carrier Supporting Carrier
Introduction In the previous post I showed some of the options to interconnect two AS so that a customer can buy a VPN in two different locations from two different SPs. There is another technology called Carrier Supporting Carrier or
CCDE – Inter AS L3 VPNs
Introduction Sometimes a customer needs a L3 VPN between two locations where the same SP is not present. This can be on a national or international basis. It would be possible to buy an Internet circuit and run an overlay
CCNA – Operation of IP Data Networks 1.2
The next topic for CCNA is: 1.2 Select the components required to meet a given network specification I wish the blueprint would have been a bit clearer on what they mean with this topic but it’s reasonable to think that
QoS Design Notes for CCDE
Trying to get my CCDE studies going again. I’ve finished the End to End QoS Design book (relevant parts) and here are my notes on QoS design. Basic QoS Different applications require different treatment, the most important parameters are: Delay:
Unique RD per PE in MPLS VPN for Load Sharing and Faster Convergence
This post describes how load sharing and faster convergence in MPLS VPNs is possible by using an unique RD per VRF per PE. It assumes you are already familiar with MPLS but here is a quick recap. The Route Distinguisher
A Quick Look at MPLS-TE
Introduction I’m currently designing and implementing a large network which will run MPLS. This network will replace an old network that was mainly L2 based and did not run MPLS, only VRF lite. There are a few customers that need
Routing Considerations in DDoS Protection Environments
Lately I have done some studying for the CCDE and one of the things I was looking at is how to protect against DDoS attacks. I’m not expecting it to be a big topic for the CCDE but it has
Some pointers on OSPF as PE to CE protocol
There was a discussion at the Cisco Learning Network (CLN) about OSPF as PE to CE protocol. I wanted to provide some pointers on using OSPF as PE to CE protocol. RFC 4577 describes how to use OSPF as PE