BGP provides routing updates that include a network number, a list of ASs that the routing information
passed through, and a list of other path attributes. BGP works with cost metrics to choose the best
available path; it sends updated router information only when one host has detected a change, and only
the affected part of the routing table is sent.
BGP communicates within one AS using Interior BGP (IBGP) because BGP does not work well with IGP.
Thus the routers inside the AS maintain two routing tables: one for the IGP and one for IBGP. BGP uses
exterior BGP (EBGP) between different autonomous systems.
BPDU
, a Bridge Protocol Data Unit is a packet that initiates communication
between devices. BPDU packets contain information on ports, addresses, priorities, and costs and they
ensure that the data ends up where it was intended to go. BPDU messages are exchanged across
bridges to detect loops in a network topology. The loops are then removed by shutting down selected
bridge interfaces and placing redundant switch ports in a backup, or blocked, state.
BSS
Basic Service Set is a wireless topology consisting of one access point connected to a wired network
and a set of wireless devices. Also called an infrastructure network. See also
CA
A Certificate Authority is a trusted third-party that generates and signs certificates. A CA may be a
commercial concern, such as GoDaddy or GeoTrust. A CA may also be an in-house server for certificates
used within an enterprise.
carrier VLAN
, carrier
s define the scope of the
, including the physical and logical ports that belong to the STPD as well as the 802.1Q
tags used to transport EMISTP- or PVST+-encapsulated BPDUs. Only one carrier VLAN can exist in any
given STPD.
CCM
CFM (Connectivity Fault Management)
, Connectivity Check Messages are frames transmitted
periodically by a
to ensure connectivity across the maintenance entities
to which the transmitting MEP belongs. The CCMs contain a unique ID for the specified domain.
Because a failure to receive a CCM indicates a connectivity fault in the network, CCMs proactively check
for network connectivity.
CDP
Cisco Discovery Protocol is a proprietary Data Link Layer protocol that shares information about other
directly connected Cisco equipment, such as operating system versions and IP addresses.
CFM
Connectivity Fault Management allows an ISP to proactively detect faults in the network for each
customer service instance individually and separately. CFM comprises capabilities for detecting,
verifying, and isolating connectivity failures in virtual bridged LANs.
CHAP
Glossary
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