Tag: frame-relay

Cisco: Configuring Compressed Real-Time Protocols

I had lately to configure compressed real-time protocols (CRTP) over a Frame-relay link.
I thought that it will be good to make a tutorial about how to configure this on the Serial interfaces (with HDLC or PPP encapsulation) and on the Frame-relay interface. Another type of interface supporting this is and ISDN interface, but the configuration there is the same like in the Serial interface case.
If you were asking why I don’t configure this on a Ethernet interface, well this is because CRTP is not supported on the Ethernet interfaces. This was just an explanation for those of you who didn’t knew this. The role of CRTP is to improve communication over low bandwidth links like Serial interfaces, Frame-relay or ISDN, and that’s why is not supported on Ethernet links (who’s speed is starting at 10 Mbps).

In the following tutorial I will configure CRTP on a Serial interface with PPP encapsulation (I chose this randomly as is the same with HDLC and ISDN) and Frame-relay interface, limit the number of header compression connections and check CRTP with “show…” commands. Since the purpose of this tutorial is CRTP the connection will no be active.

See the tutorial below:

Cisco: Multilink PPP over Frame Relay (MLPoFR)

In this tutorial I propose to show something that is not very used these days, or at least not every day, but which can be tricky if you don’t know how to approach this type of configuration. To understand this, I assume that you know the basics about PPP, FR and Multilink. I will make a short summary here but I will not go into details:

PPP or Point-to-Point protocol is used to establish direct connection between two network points. It can provide authentication, encryption privacy and compression.
FR or Frame-Relay is a telecommunication service used mostly on the WAN side towards your provider or carrier and it relay on frames for data transmission.
Multilink is used for bundle together 2 or more channels / circuits for communication improvement.

Here we will use these 3 technology to create something called MLPoFR. For security we will use authentication. Please download here the topology. Please be aware that in the topology you cannot see actually 2 links there (it a limitation of GNS3), but trust me the links are there. To be more convenient and quick the R1 of the topology is preconfigured.

Please see the tutorial below:

Frame-Relay: PVC test with ping to own interface

Let’s say that you have a link configured with Frame-Relay and from time to time you observe that the link is having some strange problems. Since you cannot be sure that the link is provided 100% error free you want to do your own tests. You want to see if the Frame-Relay between R0 and R1 is correctly configured. In order to verify this you want to set up the R0 to test the PVC to R1, by sending traffic to its own IP address.

Please download the topology here. The Frame-Relay between R0 and R1 is already configured.

See the tutorial below: