Labels and label switching, Computer Networking

An ATM network is created from interconnected ATM switches. The attachment ports or points can be connected to computers or other ATM switches. As cells reach at an ATM switch, their VPI/VCI is changed using a forwarding table that produced the new VPI/VCI for the next leg of the cell's trip.

The forwarding table is necessarily indexed by the incoming cell's VPI/VCI and the message yield the new VPI/VCI.

LABEL REWRITING:

The placement of the incoming cell's VPI/VCI with a probably distinct VPI/VCI is called rewriting.

ATM is thus known a label switching or label rewriting system. Thus two devices with a connection through an ATM network will likely have distinct VPI/VCI numbers for every end of the connection as given in the figure below.

 

2496_label rewritting.png

 

 

2327_label rewritting1.png

 

EXAMPLE:

 As an example, in the diagram we see that the sending computer S needs a VPI/VCI of 3 and transmits a cell.

 Switch A accepts the cell and looks up 3, then rewrites the VPI/VCI as 4, and transmits the cell out of its port 2.

 Switch B accepts the cell and looks up 4 then rewrites the VPI/VCI as 1 and transmits the cell at its port 2.

 Switch C accepts the cell and looks up 1 then rewrites the VPI/VCI as 6 and transmits the cell out of its port 2.

 The receiver computer R accepts the cell with a VPI/VCI of 6, which is the number it is using for the connection. Forwarding tables in every switch must be coordinated to describe meaningful 'paths' through the network.

Posted Date: 7/31/2012 7:24:18 AM | Location : United States







Related Discussions:- Labels and label switching, Assignment Help, Ask Question on Labels and label switching, Get Answer, Expert's Help, Labels and label switching Discussions

Write discussion on Labels and label switching
Your posts are moderated
Related Questions
Write discussion on Associative mapping - computer architecture.

Recognize the command that shows traffic statistics on serial0/1? Ans) show interface serial 0/1

Question: a) In a wireless network where WEP is enforced as security mechanism, what procedure would the network manager adopt for changing WEP default keys. b) Using Pla

How to define a constant variable in Java? The variable should be declared as static and final. So only one copy of the variable exists for all instances of the class and the v

With an object server, the Client/Server application is taken as a set of communicating objects. Client object commune with server objects using an Object Request Broker (ORB). The

State the specification of high-end server A mid-range or high-end server with the following specifications would be sufficient for a medium to large organisation: A Pentiu

What are the characteristics of Client/Server? Service Encapsulation of services Shared resources Asymmetrical protocols Mix-and-match Transparency of location

Create a custom chi-square function in matlab, MATLAB in Statistics

802.11 FHSS Frequency-hopping spread spectrum in a 2.4 GHz band Carrier sends on one frequency for short duration then hops to another frequency for same duration, hops agai

Question: a) In route-optimized communication, a mobile node sends packets to a correspondent using the home address present in the destination option. Why does the design use