Juniper Networks 10.4

•MSTP—MultipleSpanning TreeProtocol. A spanning-tree protocol usedto prevent

loopsin bridge configurations. Unlike other types of STPs,MSTP can block ports

selectivelyby VLAN. See also RSTP.

•OAM—Operation,Administration, and Maintenance.A set of tools used to provide

managementfor links, device, and networks.See also LFM.

•PBB—Providerbackbone bridge.

•Q-in-Q—See802.1ad.

•PBBN—Providerbackbone bridged network.

•RSTP—RapidSpanning TreeProtocol. A spanning-tree protocolused to prevent loops

inbridge configurations. RSTP is not awareof VLANs and blocks ports at the physical

level.See also MSTP.

•S-TAG—Afielddefined in the IEEE 802.1ad Q-in-Q encapsulation header that carries

theS-VLAN identifier information. See also B-TAG.

•S-taggedservice interface—Theinterface between a customer edge(CE) device and

theI-BEB or IB-BEB networkcomponents. Frames passed through this interfacecontain

anS-TAG field.See also B-tagged service interface.

•S-VLAN—Thespecific service instance VLAN identifier carriedinside the S-TAG field.

Seealso B-VID.

•switch—Anetwork device that attemptsto perform as much of the forwarding task in

hardwareas possible. The switch canfunction as a bridge (LAN switch), router, or

someother specialized device, and forwards frames, packets,or other data units. See

alsobridge.

•virtualswitch—A routing instance that can containone or more bridge domains.

•VLAN—VirtualLAN. Defines a broadcastdomain, a set of logical ports that share the

sameflooding or broadcastcharacteristics. VLANs span one or more ports on multiple

devices.By default, each VLAN maintains its own Layer2 forwarding database

containingMAC addresses learned from packetsreceived on ports belonging to the

VLAN.See also bridge domain.

•Y.1731—Theinternationalstandardfor Ethernet Frame DelayMeasurements (ETH-DM).

Atthis point, these acronyms and terms are just a bewilderingarray of letters and words.

Itis the goal of this manual to make the contents of this list familiar and allowyou to

placeeach of them in context and understandhow they relate to each other. Todo that,

abasic understanding of modern Ethernet standards and technology is necessary.

Documentation

MXSeries Ethernet Services Routers SolutionsPage•

•Networkingand Internetworking with Bridges and Routerson page 6

•NetworkAddressing at Layer 2 and Layer3 on page 7

•Networkingat Layer 2: Benefits of Ethernet Frames on page9

•Networkingat Layer 2: Challenges of EthernetMAC Addresses on page 10

•Networkingat Layer 2: Forwarding VLAN TaggedFrames on page 11

Chapter1: Overview of Ethernet Solutions