1413 should also be capable of supporting MEF 8. The IETF has several
drafts, including PsuedoWire Edge to Edge Emulation (PWE3) and CES over Packet
Switch Network, that are similar to the MEF 8 but focus on IP/MPLS networks. Because
the payload and encapsulation formats are identical, any equipment supporting these
drafts will also support MEF 8.
The MEF has essentially defined three types of CESoE that are generically portrayed
in Figure 2.19. In each case, the CES is based on a Point-to-Point connection between
two inter-working functions labelled CES IWF; this CES IWF essentially provides a
translation function with a TDM application interface on one side (customer equipment
facing) and an Ethernet interface (Service Provider network facing).
There is also an optional TDM service processor (TSP) that consists of any TDM
grooming function that may be required to convert the TDM service offered to the customer
into a form that the CES IWF can accept. For example, the TSP may be a framer
device, converting a fractional DS1 service offered to the customer into a N?—64 kbit/s
service for transport over the MEN.
Figure 2.19 Types of CESoE defined by the MEF (Source: MEF)
Metro Ethernet Network
Customer
Premises
Metro Ethernet Network
??? TDM Line Service (T-Line):
??“ Application: Leased Line Replacement
CESoETH
TDM
CES IWF CES IWF
TDM Subscriber Demarcation TDM Subscriber Demarcation
PSTN
Customer
Premises
??? TDM Access Line Service (TALS):
??“ Application: Access to a Remote Network (e.
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