Networking At Layer 2: Benefits Of Ethernet Frames - Juniper JUNOS OS 10.4 Manual

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Networking at Layer 2: Benefits of Ethernet Frames

Copyright © 2012, Juniper Networks, Inc.
Ethernet Networking
Ethernet Terms and Acronyms on page 3
Networking and Internetworking with Bridges and Routers on page 6
Networking at Layer 2: Benefits of Ethernet Frames on page 9
Networking at Layer 2: Challenges of Ethernet MAC Addresses on page 10
Networking at Layer 2: Forwarding VLAN Tagged Frames on page 11
Networking at Layer 2: Forwarding Dual-Tagged Frames on page 13
Networking at Layer 2: Logical Interface Types on page 14
A Metro Ethernet Network with MX Series Routers on page 15
Layer 2 Networking Standards on page 17
In spite of the difficulties of using a bridge to perform the network role of a router, many
vendors, customers, and service providers are attracted to the idea of using Ethernet in
as many places of their networks as possible.
The perceived benefits of Ethernet are:
Most information starts and ends inside Ethernet frames. Today, this applies to data,
as well as voice (for example, VoIP) and video (for example, Web cams).
Ethernet frames have all the essentials for networking, such as globally unique source
and destination addresses, error control, and so on.
Ethernet frames can carry any kind of packet. Networking at Layer 2 is protocol
independent (independent of the Layer 3 protocol). Layer 2 networks work for IP
packets and all other Layer 3 protocols.
More layers added to the Ethernet frame only slow the networking process down
("nodal processing delay").
Adjunct networking features such as class of service (CoS) or multicasting can be
added to Ethernet as readily as IP networks.
If more of the end-to-end transfer of information from a source to a destination can be
done in the form of Ethernet frames, more of the benefits of Ethernet can be realized on
the network. Networking at Layer 2 can be a powerful adjunct to IP networking, but it is
not usually a substitute for IP networking.
Chapter 1: Overview of Ethernet Solutions
9