Switching Glossary

Policy Configuration : Switching Glossary

Switching Glossary

Table 10. Switching glossary

BPDU

Bridge Protocol Data Unit – Used in RSTP, BPDUs are special data frames used to exchange information about bridge IDs and root path costs. BPDUs are exchanged every few seconds to allow switches to keep track of network topology and start or stop port forwarding.

CoS

Class Of Service – Cos (IEEE 802.1p) defines eight different classes of service that are indicated in a 3-bit user_priority field in an IEEE 802.1Q header added to an Ethernet frame when using tagged frames on an 802.1 network.

DSCP

Differentiated Services Code Point – Also known as DiffServ, DSCP is a networking architecture that defines a simple, coarse-grained, class-based mechanism for classifying and managing network traffic and providing Quality of Service (QoS) guarantees on IP networks. RFC 2475, published in 1998 by the IETF, defines DSCP. DSCP operates by marking an 8-bit field in the IP packet header.

IETF

Internet Engineering Task Force – The IETF is an open standards organization that develops and promotes Internet standards.

L2

OSI Layer 2 (Ethernet) – Layer 2 of the seven layer OSI model is the Data Link Layer, on which the Ethernet protocol runs. Layer 2 is used to transfer data among network entities.

LACP

Link Aggregation Control Protocol – LACP is an IEEE specification that provides a way to combine multiple physical ports together to form a single logical channel. LACP allows load balancing by the connected devices.

LLDP

Link Layer Discovery Protocol (IEEE 802.1AB) – LLDP is a Layer 2 protocol used by network devices to communicate their identity, capabilities, and interconnections. This information is stored in a MIB database on each host, which can be queried with SNMP to determine the network topology. The information includes system name, port name, VLAN name, IP address, system capabilities (switching, routing), MAC address, link aggregation, and more.

LLTD

Link Layer Topology Discovery (Microsoft Standard) – LLTD is a Microsoft proprietary protocol with functionality similar to LLDP. It operates on wired or wireless networks (Ethernet 802.3 or wireless 802.11). LLTD is included on Windows Vista and Windows 7, and can be installed on Windows XP.

PDU

Protocol Data Unit – In the context of the Switching feature, the Layer 2 PDU is the frame. It contains the link layer header followed by the packet.

RSTP

Rapid Spanning Tree Protocol (IEEE 802.1D-2004) – RSTP was defined in 1998 as an improvement to Spanning Tree Protocol. It provides faster spanning tree convergence after a topology change.

BPDU	Bridge Protocol Data Unit – Used in RSTP, BPDUs are special data frames used to exchange information about bridge IDs and root path costs. BPDUs are exchanged every few seconds to allow switches to keep track of network topology and start or stop port forwarding.
CoS	Class Of Service – Cos (IEEE 802.1p) defines eight different classes of service that are indicated in a 3-bit user_priority field in an IEEE 802.1Q header added to an Ethernet frame when using tagged frames on an 802.1 network.
DSCP	Differentiated Services Code Point – Also known as DiffServ, DSCP is a networking architecture that defines a simple, coarse-grained, class-based mechanism for classifying and managing network traffic and providing Quality of Service (QoS) guarantees on IP networks. RFC 2475, published in 1998 by the IETF, defines DSCP. DSCP operates by marking an 8-bit field in the IP packet header.
IETF	Internet Engineering Task Force – The IETF is an open standards organization that develops and promotes Internet standards.
L2	OSI Layer 2 (Ethernet) – Layer 2 of the seven layer OSI model is the Data Link Layer, on which the Ethernet protocol runs. Layer 2 is used to transfer data among network entities.
LACP	Link Aggregation Control Protocol – LACP is an IEEE specification that provides a way to combine multiple physical ports together to form a single logical channel. LACP allows load balancing by the connected devices.
LLDP	Link Layer Discovery Protocol (IEEE 802.1AB) – LLDP is a Layer 2 protocol used by network devices to communicate their identity, capabilities, and interconnections. This information is stored in a MIB database on each host, which can be queried with SNMP to determine the network topology. The information includes system name, port name, VLAN name, IP address, system capabilities (switching, routing), MAC address, link aggregation, and more.
LLTD	Link Layer Topology Discovery (Microsoft Standard) – LLTD is a Microsoft proprietary protocol with functionality similar to LLDP. It operates on wired or wireless networks (Ethernet 802.3 or wireless 802.11). LLTD is included on Windows Vista and Windows 7, and can be installed on Windows XP.
PDU	Protocol Data Unit – In the context of the Switching feature, the Layer 2 PDU is the frame. It contains the link layer header followed by the packet.
RSTP	Rapid Spanning Tree Protocol (IEEE 802.1D-2004) – RSTP was defined in 1998 as an improvement to Spanning Tree Protocol. It provides faster spanning tree convergence after a topology change.