Chapter 50: VLAN Stacking
684
Section VII: Virtual LANs
Overview
VLAN stacking is a way to label tagged and untagged packets with new
802.1Q headers. In the case of tagged packets, which already contain
802.1Q headers, VLAN stacking adds the new headers so that they
coexist with the native headers in the packets.
This feature is intended for metro Ethernet providers. It allows them to
uniquely label the individual packets of the customer traffic they transport
over their networks, without having to delete any existing headers.
The headers consist of an EtherType value and a VLAN ID (VID). They
are added as the customer packets enter the metro network networks and
are removed when the packets reenter the customer networks. Thus, the
packets reemerge unchanged on the customer networks, making the
transition over the metro networks transparent to the customers.
VLAN stacking provides metro Ethernet providers with an alternative to
using the native 802.1Q headers to identify and separate the private traffic
flows that they transport across their public networks. In general, packets
contain, at most, one 802.1Q header with one VID that identifies the
VLAN, or broadcast domain, to which the node that generated a packet
belongs. The drawback to using native headers is that different customers
are likely to use the same VIDs in their networks. And requiring that
customers reconfigure their VLANs by assigning unique VIDs not used by
other customers is likely to be impractical.
VLAN stacking also provides a means for identifying packets that do not
have 802.1Q headers, and therefore lack VIDs. VLAN memberships of
packets without VIDs, referred to as untagged packets, are determined by
the VIDs assigned to the ports on which the packets are received on the
switches.
An 802.1Q header consists of two values. It has a VID and an EtherType/
Length value, which specifies either the protocol or the length of the data
in the payload of a packet. VLAN stacking allows you to set both of these
values.
The process of adding the extra 802.1Q header to packets is called
encapsulation. It occurs at the point when packets leave a customer’s
network, prior to entering the metro Ethernet network. In the case of
tagged packets, the extra 802.1Q header with the new EtherType/Length
and VID values is added in front of the customer’s 802.1Q header. The
resulting packets have two VIDs, referred to as inner and outer VIDs. The
outer VID belongs to the metro provider and the inner VID to the customer.
A metro provider refers only to the outer VID when transporting packets
across its network and ignores the inner VID. The outer VID resides in the
packets only while the packets traverse their network and is removed
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Страница 4: ......
Страница 26: ...Contents 26...
Страница 30: ...Tables 30...
Страница 36: ...36 Section I Getting Started...
Страница 70: ...Chapter 2 Starting a Management Session 70 Section I Getting Started...
Страница 96: ...96 Section II Basic Operations...
Страница 142: ...Chapter 6 Basic Switch Management Commands 142 Section II Basic Operations...
Страница 220: ...Chapter 9 IPv4 and IPv6 Management Addresses 220 Section II Basic Operations...
Страница 244: ...Chapter 10 IPv4 and IPv6 Management Address Commands 244 Section II Basic Operations...
Страница 264: ...Chapter 12 SNTP Client Commands 264 Section II Basic Operations...
Страница 298: ...Chapter 15 Enhanced Stacking 298 Section II Basic Operations...
Страница 312: ...Chapter 16 Enhanced Stacking Commands 312 Section II Basic Operations...
Страница 318: ...Chapter 17 Port Mirror 318 Section II Basic Operations...
Страница 324: ...Chapter 18 Port Mirror Commands 324 Section II Basic Operations Example awplus show mirror...
Страница 350: ...Chapter 21 Multicast Commands 350 Section II Basic Operations...
Страница 352: ...352 Section III File System...
Страница 360: ...Chapter 22 File System 360 Section III File System...
Страница 383: ...AT 9000 Switch Command Line User s Guide Section III File System 383 Example awplus show boot...
Страница 386: ...Chapter 25 Boot Configuration File Commands 386 Section III File System...
Страница 398: ...Chapter 26 File Transfers 398 Section III File System...
Страница 406: ...Chapter 27 File Transfer Commands 406 Section III File System...
Страница 408: ...408 Section IV Event Messages...
Страница 430: ...Chapter 30 Syslog Client 430 Section IV Event Messages...
Страница 438: ...438 Section V Port Trunks...
Страница 448: ...Chapter 32 Static Port Trunks 448 Section V Port Trunks...
Страница 480: ...480 Section VI Spanning Tree Protocols...
Страница 500: ...Chapter 36 Spanning Tree and Rapid Spanning Tree Protocols 500 Section VI Spanning Tree Protocols...
Страница 520: ...Chapter 38 STP Commands 520 Section VI Spanning Tree Protocols...
Страница 542: ...Chapter 40 RSTP Commands 542 Section VI Spanning Tree Protocols Example awplus show spanning tree...
Страница 558: ...558 Section VII Virtual LANs...
Страница 600: ...Chapter 42 Port based and Tagged VLAN Commands 600 Section VII Virtual LANs...
Страница 634: ...Chapter 44 GARP VLAN Registration Protocol Commands 634 Section VII Virtual LANs...
Страница 670: ...Chapter 47 Private Port VLANs 670 Section VII Virtual LANs...
Страница 692: ...Chapter 50 VLAN Stacking 692 Section VII Virtual LANs...
Страница 698: ...Chapter 51 VLAN Stacking Commands 698 Section VII Virtual LANs...
Страница 700: ...700 Section VIII Port Security...
Страница 748: ...Chapter 54 802 1x Port based Network Access Control 748 Section VIII Port Security...
Страница 790: ...Chapter 55 802 1x Port based Network Access Control Commands 790 Section VIII Port Security...
Страница 792: ...792 Section IX Simple Network Management Protocols...
Страница 804: ...Chapter 56 SNMPv1 and SNMPv2c 804 Section X Simple Network Management Protocols...
Страница 852: ...852 Section X Network Management...
Страница 976: ...Chapter 63 Address Resolution Protocol ARP 976 Section X Network Management...
Страница 1090: ...1090 Section XI Management Security...
Страница 1114: ...Chapter 71 Telnet Server 1114 Section XI Management Security...
Страница 1122: ...Chapter 73 Telnet Client 1122 Section XI Management Security...
Страница 1126: ...Chapter 74 Telnet Client Commands 1126 Section XI Management Security...
Страница 1138: ...Chapter 75 Secure Shell SSH Server 1138 Section XI Management Security...
Страница 1158: ...Chapter 78 Non secure HTTP Web Browser Server Commands 1158 Section XI Management Security...
Страница 1186: ...Chapter 80 Secure HTTPS Web Browser Server Commands 1186 Section XI Management Security...
Страница 1202: ...Chapter 81 RADIUS and TACACS Clients 1202 Section XI Management Security...
Страница 1230: ...Chapter 82 RADIUS and TACACS Client Commands 1230 Section XI Management Security...
Страница 1244: ...Chapter System Monitoring Commands 1244...
Страница 1278: ...Index 1278 Configuration mode 644 659 VLAN SET MACADDRESS command Port Interface mode 644 661 W WRITE command 75 94 385...