Chapter 16 CE-100T-8 Ethernet Operation
CE-100T-8 SONET Circuits and Features
CE-100T-8 VCAT Characteristics
The ML-100T-8 card and the CE-100T-8 card (both the ONS 15310-CL version and the ONS 15454 SONET/SDH version) have hardware-based support for the ITU-T G.7042 standard link capacity adjustment scheme (LCAS). This allows the user to dynamically resize a high order or low order VCAT circuit through CTC or TL1 without affecting other members of the VCG (errorless). ML-100T-8 LCAS support is high order only and is limited to a two member VCG.
The ONS 15454 SONET/SDH ML-Series card has a software-based LCAS (SW-LCAS) scheme. This scheme is also supported by both the ML-100T-8 card and both versions of the CE-100T-8, but only for circuits terminating on a ONS 15454 SONET/SDH ML-Series card.
The CE-100T-8 card allows independent routing and protection preferences for each member of a VCAT circuit. The user can also control the amount of VCAT circuit capacity that is fully protected, unprotected or if the circuit is on a bidirectional line switched ring (BLSR), uses protection channel access (PCA). Alarms are supported on a per-member as well as per virtual concatenation group (VCG) basis.
Note The maximum tolerable VCAT differential delay for the CE-100T-8 is 48 milliseconds. The VCAT differential delay is the relative arrival time measurement between members of a virtual concatenation group (VCG).
CE-100T-8 POS Encapsulation, Framing, and CRC
The CE-100T-8 uses Cisco EoS LEX (LEX). LEX is the primary encapsulation of ONS Ethernet cards. In this encapsulation the protocol field is set to the values specified in Internet Engineering Task Force (IETF) Request For Comments (RFC) 1841. The user can provision GPF-F framing (default) or high-level data link control (HDLC) framing. With GFP-F framing, the user can also configure a 32-bit CRC (the default) or no CRC (none). When LEX is used over GFP-F it is standard Mapped Ethernet over GFP-F according to ITU-T G.7041. HDLC framing provides a set 32-bit CRC.
Figure 16-5illustrates CE-100T-8 framing and encapsulation.
Figure 16-5 ONS CE-100T-8 Encapsulation and Framing Options
| GFP-F Frame Types |
| | | |
Encapsulation | | GFP-Mapped | |
| Ethernet (LEX) | |
| | |
| | | |
Flag | Address | Control | Protocol | Payload | FCS | |
| | | | | | |
| | HDLC Framing Mode | | or |
| Core | Payload | Payload | FCS |
| Header | Header |
| | |
| | | | |
GFP-F Framing Mode
SONET/SDH Payload Envelope
SONET/SDH Frame
Cisco ONS 15310-CL Ethernet Card Software Feature and Configuration Guide, R5.0
