Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 2196)

Appendix B: Glossary
Software Reference for x310 Series Switches
B.6 AlliedWare Plus TM Operating System - Version 5.4.4C C613-50046-01 REV A
C
CHAP
Challenge Handshake Authentication Protocol. CHAP is an authentication method used
by PPP servers to validate the identity of clients. CHAP verifies the identity of the client by
using a three-way handshake, and the verification is based on a shared secret by the client
and the server, such as the client's password.
CIST
Common and Internal Spanning Tree. The CIST is the default spanning tree instance of
MSTP , i.e. all VLANs that are not members of particular MSTIs are members of the CIST.
Also, an individual MST region can be regarded as a single virtual bridge by other MST
regions. The spanning tree that runs between regions is the CIST. The CIST is also the
spanning tree that runs between MST regions and Single Spanning Tree (SST) entities.
For more information see “Common and Internal Spanning Tree (CIST)” on page 18.15 .
Classification
In ACLs and QoS , classification is the process of filtering and marking. Filtering involves
sorting your data into appropriate traffic types. Marking involves tagging the data so that
downstream ports and routers can apply appropriate service policy rules. There are two
reasons to classify data:
■ To provide network security (security ACLs).
■ To apply service quality criteria QoS.
The main application of security ACLs is to block undesired traffic. When using ACLs
though QoS, the same classification and action abilities are available, but QoS has some
additional fields that it can match on and also provides the ability to perform metering,
marking and remarking on packets that match the filter definitions.
For more information on QoS classification see “Classifying your Data” on page 38.8 .
Class maps
Class maps are among the pivotal QoS components. They provide the means that
associate the classified traffic with its appropriate QoS actions. They are the linking
elements for the following functions:
■ Classification .
■ policy mapping. See Policy maps .
■ Premarking .
The relationship between a class map and a policy map can be one-to-one or many-to-
one.
For more information see “Class Maps” on page 38.8 .
CLI
Command Line Interface. With three distinct modes, the CLI is very secure. In User exec
mode you can view settings and troubleshoot problems but you cannot make changes to
the system. In Privileged exec mode you can change system settings and restart the
device. You can only make configuration changes in Global configuration mode, which
reduces the risk of making accidental configuration changes.
For more information see “How to Work with Command Modes” on page 1.7 .