User manual ZYXEL ES-4124

[. . . ] ES-4124 Intelligent Layer 3+ Switch User's Guide Version 3. 70 8/2006 ES-4124 User's Guide Copyright Copyright © 2006 by ZyXEL Communications Corporation. The contents of this publication may not be reproduced in any part or as a whole, transcribed, stored in a retrieval system, translated into any language, or transmitted in any form or by any means, electronic, mechanical, magnetic, optical, chemical, photocopying, manual, or otherwise, without the prior written permission of ZyXEL Communications Corporation. All rights reserved. Disclaimer ZyXEL does not assume any liability arising out of the application or use of any products, or software described herein. Neither does it convey any license under its patent rights nor the patent rights of others. [. . . ] Select a queue (Q0 to Q7) to have the switch use Strictly Priority to service the subsequent queue(s) after and including the specified queue for the gigabit ports. For example, if you select Q5, the switch services traffic on Q5, Q6 and Q7 using Strictly Priority. Click Apply to save your changes to the switch's run-time memory. The switch loses these changes if it is turned off or loses power, so use the Save link on the top navigation panel to save your changes to the non-volatile memory when you are done configuring. Click Cancel to reset the fields. Apply Cancel 152 Chapter 20 Queuing Method ES-4124 User's Guide CHAPT E R 2 1 VLAN Stacking This chapter shows you how to configure VLAN stacking on your switch. See the chapter on VLANs for more background information on Virtual LAN 21. 1 VLAN Stacking Overview A service provider can use VLAN stacking to allow it to distinguish multiple customers VLANs, even those with the same (customer-assigned) VLAN ID, within its network. Use VLAN stacking to add an outer VLAN tag to the inner IEEE 802. 1Q tagged frames that enter the network. By tagging the tagged frames ("double-tagged" frames), the service provider can manage up to 4, 094 VLAN groups with each group containing up to 4, 094 customer VLANs. This allows a service provider to provide different service, based on specific VLANs, for many different customers. A service provider's customers may require a range of VLANs to handle multiple applications. A service provider's customers can assign their own inner VLAN tags on ports for these applications. Therefore, there is no VLAN tag overlap among customers, so traffic from different customers is kept separate. 21. 1. 1 VLAN Stacking Example In the following example figure, both A and B are Service Provider's Network (SPN) customers with VPN tunnels between their head offices and branch offices respectively. The service provider can separate these two VLANs within its network by adding tag 37 to distinguish customer A and tag 48 to distinguish customer B at edge device 1 and then stripping those tags at edge device 2 as the data frames leave the network. Chapter 21 VLAN Stacking 153 ES-4124 User's Guide Figure 66 VLAN Stacking Example 21. 2 VLAN Stacking Port Roles Each port can have three VLAN stacking "roles", Normal, Access Port and Tunnel (the latter is for Gigabit ports only). · Select Normal for "regular" (non-VLAN stacking) IEEE 802. 1Q frame switching. · Select Access Port for ingress ports on the service provider's edge devices (1 and 2 in the VLAN stacking example figure). The incoming frame is treated as "untagged", so a second VLAN tag (outer VLAN tag) can be added. Note: Static VLAN Tx Tagging MUST be disabled on a port where you choose Normal or Access Port. · Select Tunnel Port (available for Gigabit ports only) for egress ports at the edge of the service provider's network. All VLANs belonging to a customer can be aggregated into a single service provider's VLAN (using the outer VLAN tag defined by SP VID). Note: Static VLAN Tx Tagging MUST be enabled on a port where you choose Tunnel Port. 21. 3 VLAN Tag Format A VLAN tag (service provider VLAN stacking or customer IEEE 802. 1Q) consists of the following three fields. Table 48 VLAN Tag Format Type Priority VID 154 Chapter 21 VLAN Stacking ES-4124 User's Guide Type is a standard Ethernet type code identifying the frame and indicates that whether the frame carries IEEE 802. 1Q tag information. SP TPID (Service Provider Tag Protocol Identifier) is the service provider VLAN stacking tag type. · If the VLAN stacking port role is Access Port, then the switch adds the SP TPID tag to all incoming frames on the service provider's edge devices (1 and 2 in the VLAN stacking example figure). [. . . ] The "borrowed" host ID bit can be either "0" or "1" thus giving two subnets; 192. 168. 1. 0 with mask 255. 255. 255. 128 and 192. 168. 1. 128 with mask 255. 255. 255. 128. Note: In the following charts, shaded/bolded last octet bit values indicate host ID bits "borrowed" to make network ID bits. The number of "borrowed" host ID bits determines the number of subnets you can have. The remaining number of host ID bits (after "borrowing") determines the number of hosts you can have on each subnet. Table 124 Subnet 1 IP/SUBNET MASK IP Address IP Address (Binary) Subnet Mask Subnet Mask (Binary) NETWORK NUMBER 192. 168. 1. [. . . ]