User manual ZYXEL GS-2024

[. . . ] Dimension GS-2024 Gigabit Ethernet switch User's Guide Version 3. 60 8/2005 GS-2024 User's Guide Copyright Copyright © 2005 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 port where the MAC address entered in the previous field will be automatically forwarded. This field displays whether this static MAC address forwarding rule is active (Yes) or not (No). This field displays the descriptive name for identification purposes for this static MAC address-forwarding rule. This field displays the MAC address that will be forwarded and the VLAN identification number to which the MAC address belongs. This field displays the port where the MAC address shown in the next field will be forwarded. 88 Chapter 9 Static MAC Forwarding GS-2024 User's Guide Table 18 Static MAC Forwarding (continued) LABEL Delete Cancel DESCRIPTION Click Delete to remove the selected entry from the summary table. Click Cancel to clear the Delete check boxes. Chapter 9 Static MAC Forwarding 89 GS-2024 User's Guide 90 Chapter 9 Static MAC Forwarding GS-2024 User's Guide CHAPT E R 1 0 Spanning Tree Protocol This chapter introduces the Spanning Tree Protocol (STP). 10. 1 Overview STP detects and breaks network loops and provides backup links between switches, bridges or routers. It allows a switch to interact with other STP-compliant switches in your network to ensure that only one route exists between any two stations on the network. 10. 1. 1 STP Terminology The root bridge is the base of the spanning tree; it is the bridge with the lowest identifier value (MAC address). Path cost is the cost of transmitting a frame onto a LAN through that port. It is assigned according to the speed of the link to which a port is attached. The slower the media, the higher the cost. Table 19 STP Path Costs LINK SPEED RECOMMENDED VALUE Path Cost 4Mbps Path Cost 10Mbps Path Cost 16Mbps Path Cost 100Mbps Path Cost 1Gbps Path Cost 10Gbps 250 100 62 19 4 2 RECOMMENDED RANGE 100 to 1000 50 to 600 40 to 400 10 to 60 3 to 10 1 to 5 ALLOWED RANGE 1 to 65535 1 to 65535 1 to 65535 1 to 65535 1 to 65535 1 to 65535 On each bridge, the root port is the port through which this bridge communicates with the root. It is the port on this switch with the lowest path cost to the root (the root path cost). If there is no root port, then this switch has been accepted as the root bridge of the spanning tree network. This bridge has the lowest cost to the root among the bridges connected to the LAN. Chapter 10 Spanning Tree Protocol 91 GS-2024 User's Guide 10. 1. 2 How STP Works After a bridge determines the lowest cost-spanning tree with STP, it enables the root port and the ports that are the designated ports for connected LANs, and disables all other ports that participate in STP. Network packets are therefore only forwarded between enabled ports, eliminating any possible network loops. STP-aware switches exchange Bridge Protocol Data Units (BPDUs) periodically. When the bridged LAN topology changes, a new spanning tree is constructed. Once a stable network topology has been established, all bridges listen for Hello BPDUs (Bridge Protocol Data Units) transmitted from the root bridge. If a bridge does not get a Hello BPDU after a predefined interval (Max Age), the bridge assumes that the link to the root bridge is down. This bridge then initiates negotiations with other bridges to reconfigure the network to re-establish a valid network topology. 10. 1. 3 STP Port States STP assigns five port states to eliminate packet looping. A bridge port is not allowed to go directly from blocking state to forwarding state so as to eliminate transient loops. Table 20 STP Port States PORT STATE DESCRIPTION Disabled Blocking Listening Learning Forwarding STP is disabled (default). Information frames are submitted to the learning process but not forwarded. All information frames are received and forwarded. 10. 2 STP Status Click Advanced Application, Spanning Tree Protocol in the navigation panel to display the status screen as shown next. 92 Chapter 10 Spanning Tree Protocol GS-2024 User's Guide Figure 38 Spanning Tree Protocol: Status The following table describes the labels in this screen. Table 21 Spanning Tree Protocol: Status LABEL Spanning Tree Protocol Configuration Bridge Bridge ID DESCRIPTION This field displays Running if STP is activated. [. . . ] 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 75 Subnet 1 NETWORK NUMBER IP Address IP Address (Binary) Subnet Mask Subnet Mask (Binary) Subnet Address: 192. 168. 1. 0 Broadcast Address: 192. 168. 1. 127 192. 168. 1. Lowest Host ID: 192. 168. 1. 1 Highest Host ID: 192. 168. 1. 126 LAST OCTET BIT VALUE 0 00000000 128 10000000 Table 76 Subnet 2 NETWORK NUMBER IP Address IP Address (Binary) Subnet Mask Subnet Mask (Binary) Subnet Address: 192. 168. 1. 128 Broadcast Address: 192. 168. 1. 255 192. 168. 1. Lowest Host ID: 192. 168. 1. 129 Highest Host ID: 192. 168. 1. 254 LAST OCTET BIT VALUE 128 10000000 128 10000000 The remaining 7 bits determine the number of hosts each subnet can have. [. . . ]