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virtual concatenation (SDH) (VCAT)

Virtual Concatenation (VCAT) is an ANSI standardized protocol that supports better adaptation of diverse traffic to SDH networks. It is a concatenation technique used in the Next Generation Synchronous Digital Hierarchy( NG-SDH) to adapt asynchronous data streams to the Synchronous Digital Hierarchy (SDH).

Using Virtual Concatenation (VCAT), packet-oriented traffic from Ethernet, storage networks, or other traffic can be transmitted as a concatenated payload. According to the procedure, the payloads of many small containers are concatenated to form a large group, the Virtual Concatenation Group( VCG). The VCAP protocol is particularly interesting for service providers because it combines the payload data of the packet networks into larger units and thus transmits them more efficiently. This makes much better use of the existing infrastructure of the transport networks. Virtual Concatenation allows the network operator to adapt the transport capacity of the SDH network to the services offered. This means that the transmission rates of the synchronous transmission mode, STM-n, can be used more efficiently. Adapting the service to the STM transmission rates thus ensures better capacity utilization.

The increase in efficiency will be explained using Gigabit Ethernet as an example. If Gigabit Ethernet is transmitted via an STM-16 channel at a user data rate of 2.396 Gbit/s, the utilization rate is around 42%. Using the concatenation technique and intelligent grouping (VCG), the same service can be transmitted over seven VC-4 containers(VC-4-7v) with a capacity utilization of approx. 85 %.

The necessary information is transmitted in the path header part of the individual virtual containers (VC).

Informations:
Englisch: virtual concatenation (SDH) - VCAT
Updated at: 14.10.2012
#Words: 249
Links: American national standards institute (ANSI), protocol, traffic, synchronous digital hierarchy (SDH), next generation SDH (NG-SDH)
Translations: DE
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