CHAPTER1
Overview of Ethernet Solutions•EthernetTerms and Acronymson page 3
•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
•Networkingat Layer 2: Forwarding Dual-TaggedFrames on page 13
•Networkingat Layer 2: Logical InterfaceTypes on page 14
•AMetro Ethernet Network with MX Series Routers on page15
•Layer2 Networking Standards on page 17
EthernetTerms and Acronyms
Networkingwith a switch over Ethernet on a LAN is different than networkingwith a
routerwith IP over a wider area. Even the wordsused to talk about Ethernet networking
aredifferent from those used in IP routing. This topic providesa list of all the terms and
acronymsused in the Junos OS Layer 2 ConfigurationGuide, as well terms that apply to
acomplete network using Ethernet as a carrier technology.
•802.1ad—TheIEEE specificationfor “Q-in-Q” encapsulation and bridging of Ethernet
frames.
•802.1ah—TheIEEE specification formedia access control (MAC) tunneling
encapsulationand bridging of Ethernet frames acrossa provided backbone-managed
bridge.
•802.3ag—TheIEEEspecification for a wide rangeof Ethernet Operations, Administration,
andMaintenance (OAM) features.See also OAM,CFM, and ETH-DM.
•802.3ah—TheIEEE specification for link faultmanagement (LFM), a method for OAM
ofEthernet links.
•802.1Q—TheIEEE specification foradding virtual local area network (VLAN) tags to
anEthernet frame.
•B–MAC—Thebackbone sourceand destination MAC address fields found in the IEEE
802.1ahprovider MAC encapsulation header.
3Copyright© 2010, Juniper Networks,Inc.