As noted in Chapter 6, "MSPP Network Design Example: Cisco ONS 15454," the ONS 15454 Multiservice Provisioning Platform (MSPP) provides multiple types of Ethernet interface cards for a variety of applications. These interface cards fall into two broad categories: transport (Layer 1) Ethernet interfaces and multilayer (Layer 2 and Layer 3) Ethernet interfaces. The following is a categorization and brief description of each of the Ethernet interface cards covered in this chapter:
Typically, each series (or family) of ONS 15454 Ethernet cards is used in a SONET/SDH network. For example, ML-Series cards are used to interoperate with other ML-Series cards within a SONET/SDH ring. However, some Ethernet cards from different series can interconnect with each other using circuits configured between their respective Packet over SONET/SDH (POS) interfaces. The limitation of mixing these types to interoperate in a network is that they are limited to frame-forwarding (Layer 1) functionality only. So, for example, if a circuit is built between the POS interface of an ML-Series card and the POS interface of a G-Series card, the switch features of the ML-Series card (such as VLANs) are not supported. To achieve Ethernet card POS interoperability between cards of dissimilar series, the POS encapsulation type (LEX, for example), the cyclic redundancy check (CRC) size, and the framing mode (HDLC, for example) must match at the POS endpoints. It is possible to interoperate cards in the ML Series, G Series, and CE Series. However, the E-Series cards use proprietary E-Series encapsulation and do not support POS interoperability with any of the other Ethernet card series. |