Cabletron Systems 9A426-01 User Manual

 

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9A426-01/9A426-02 Module Specific Information

 

To modify fields on these modules, you must have read-write or super-user 
privileges. If you have read-only privileges, you can view information; however, 
you cannot modify any fields.

 

Rather than addressing cells to a specific destination, as in a LAN, ATM addresses 
cells to Virtual Channels (VCs) and/or Virtual Paths (VPs). This addressing takes 
place in the header field of the ATM cell.

VCs and VPs are bi-directional (i.e., they transfer information in both directions 
on a single channel or path) and are “set up” between devices on the ATM 
network prior to transmission. Similar to WAN transmission, ATM technology 
provides the ability of sending several VCs together over a VP, and several VPs 
over an ATM link segment.

 

ATM networks use two different types of Virtual Channels:

•

Permanent Virtual Channels (PVCs)

•

Switched Virtual Channels (SVCs).

The difference between PVCs and SVCs exists in the channel setup.

PVCs are pre-configured by an administration function, and are usually 
established for long-term use. After setting up this channel, nothing else is 
required by the network to transfer information between the two established 
points. This type of virtual channelling is established through a local or remote 
management interface.

SVCs use a signaling and network switching procedure to set up dynamically. In 
other words, SVCs are established “on the fly,” as needed for a particular service, 
used to transmit on the short term, and then terminated.