Extreme Networks ExtremeWare XOS Guide Manual page 458

Glossary
C (continued)
cluster
control VLAN
CRC
CRC error
D
DA
default encapsulation mode
designated port
Device Manager
DF
ExtremeWare XOS 11.1 Concepts Guide
In BGP, a cluster is formed within an AS by a route reflector and its
client routers.
In EAPS, the control VLAN is a VLAN that sends and receives EAPS
messages. You must configure one control VLAN for each EAPS
domain.
Cyclic redundancy check. This simple checksum is designed to detect
transmission errors. A decoder calculates the CRC for the received
data and compares it to the CRC that the encoder calculated, which is
appended to the data. A mismatch indicates that the data was
corrupted in transit.
Cyclic redundancy check error. This is an error condition in which the
data failed a checksum test used to trap transmission errors. These
errors can indicate problems anywhere in the transmission path.
Destination address. The DA is the IP or MAC address of the device
that is to receive the packet.
In STP, default encapsulation allows you to specify the type of BPDU
encapsulation to use for all ports added to a given STPD, not just to
one individual port. The encapsulation modes are:
802.1d—This mode is used for backward compatibility with
●
previous STP versions and for compatibility with third-party
switches using IEEE standard 802.1d.
EMISTP—Extreme Multiple Instance Spanning Tree Protocol
●
(EMISTP) mode is an extension of STP that allows a physical port
to belong to multiple STPDs by assigning the port to multiple
VLANs.
PVST+—This mode implements PVST+ in compatibility with third-
●
party switches running this version of STP.
In STP, the designated port provides the shortest path connection to
the root bridge for the attached LAN segment. Each LAN segment has
only one designated port.
The Device Manager is an Extreme Networks-proprietary process that
runs on every node and is responsible for monitoring and controlling
all of the devices in the system. The Device Manager is useful for
system redundancy.
Don't fragment bit. This is the don't fragment bit carried in the flags
field of the IP header that indicates that the packet should not be
fragmented. The remote host will return ICMP notifications if the
packet had to be split anyway, and these are used in MTU discovery.
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