Did You Know that cVu can Strip MPLS Headers?

What exactly is MPLS and what are its benefits?

Multi-Protocol Label Switching (MPLS) provides an effective mechanism within computer network infrastructures to speed up the time it takes a data packet to travel from one node to another. It allows computer networks to operate faster and manage easier by using short path labels instead of long network addresses for routing network packets. It was originally developed in the late 1990s to provide faster packet forwarding for IP routers, but since then, its capabilities have expanded tremendously. The unique feature of MPLS is its use of labeling. In a traditional IP network, each router performs an IP lookup, determines a next “hop” based on its routing table, and forwards the packet to that next “hop”. MPLS on the other hand, performs “label switching”. So rather than finding a next “hop”, it finds the destination router as well as finding the pre-determined path to get to that final router. Future routers will use the label to route the traffic without having to perform any additional IP lookups. Once it arrives at its destination, the router label is removed, and the packet is delivered via normal IP routing. Think of this process as mailing a letter. Those that don’t use label switching, for example, will send the letter via postal mail with a destination address that is examined by the postal service. The address on the envelope will determine how the mail handler will deliver the envelope to the final destination. Label switching on the other hand, follows a different process. Instead of a destination address being used to make the routing decision, a label value is placed on the envelope, and is used instead of the postal address to route the mail to the recipient. In technical terms, a label is placed in a packet header and is used to direct the traffic to its destination.

Benefits of MPLS:

There are several key advantages of MPLS, most of which have to do with the way it is designed:

  1. Faster speed: Because of its labeling technology, the speed of performing lookups for destinations and routing is much faster than traditional IP table lookups. This lookup requires only one access to the table, in contrast to a traditional routing table access that might require several thousand lookups. The result is a more efficient operation that reduces delay and response time.
  2. Scalable: If you think of how many new users sign on to the Internet every day, the numbers are astonishing. And if you factor in the number of routers and servers that must support this demand, you can only imagine the arduous task that these devices have in order to keep track of all these users. Fortunately, label switching offers solutions to this rapid growth by allowing many IP addresses to be associated with one or a few labels. This approach will further reduce the size of address tables, allowing a router to support more users.
  3. Quality of service-  A distinct feature of MPLS is the ability to manage and control quality of service (QoS). Because MPLS works with a system of labels, customers can determine prioritization levels associated with those labels. Furthermore, MPLS networks can assign priorities to the different packets based on what the labels say about that packet. For example, packets with greater priority such as voice and video would be given more bandwidth allocation versus a low priority packet such as sending a document online.

Despite the multiple benefits of MPLS, it isn’t problem free. One issue is that the MPLS header is an overhead that loads other network monitoring tools. Unfortunately, these tools are not adequately designed to handle the extra information that comes with MPLS headers. This results in longer troubleshooting time and the inaccurate analysis of network behavior.

How can cPacket’s cVu help?

cPacket’s cVu addresses this problem by allowing the user to strip the MPLS labels from the packets at line speed. Stripping the MPLS labels will reduce the overhead on other tools when they capture and process packets, allowing them to work more efficiently. Furthermore, cVu is capable of stripping one to three MPLS labels.

Enabling MPLS stripping is simple. In the general configuration page, the user can set the parameter ‘mpls_strip_enable_on’ to determine which ports to strip the labels. For example, to remove MPLS labels from network traffic entering ports 1, 7, 9 and 11 of the cVu, the user enter the following configuration:

mpls_strip_enable_on 1, 7, 9, 11

With cPacket’s cVu, users will benefit from accurate data, faster time to resolution, and the visibility they need to proactively detect and solve any issues in the network. To learn more about cVu, please contact us.