Cisco Systems BC-23 manual Routing between ISL VLANs, BC-32

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Configuring Transparent Bridging

Transparent and SRT Bridging Configuration Task List

To configure a VLAN on a transparently bridged network, use the following commands beginning in global configuration mode:

 

Command

Purpose

Step 1

 

 

interface type

Specifies a subinterface.

 

slot/port.subinterface-number

 

Step 2

 

 

encapsulation sde said

Specifies the IEEE 802.10 Security data exchange security association

 

 

identifier (in other words, specifies the “color”).

Step 3

 

 

bridge-group bridge-group

Associates the subinterface with an existing bridge group.

 

 

 

Transparently bridged VLANs are supported in conjunction with only the IEEE Spanning-Tree Protocol. When you logically segment a transparently bridged network into VLANs, each VLAN computes its own spanning-tree topology. Configuring each VLAN to compute its own spanning-tree topology provides much greater stability than running a single spanning tree throughout. Traffic bridged within one VLAN is unaffected by physical topology changes occurring within another VLAN.

Note The current implementation of SDE encapsulation is not recommended for serial or

Ethernet media.

Routing between ISL VLANs

Our VLAN Routing implementation is designed to operate across all router platforms. However, the Inter-Switch Link (ISL) VLAN trunking protocol currently is defined on 100 BaseTX/FX Fast Ethernet interfaces only and therefore is appropriate to the Cisco 7000 and higher-end platforms only. The IEEE

802.10protocol can run over any LAN or HDLC serial interface. VLAN traffic is fast switched. The actual format of these VLAN encapsulations are detailed in the IEEE Standard 802.10-1992 Secure Data Exchange and in the Inter-Switch Link (ISL) Protocol Specification.

Our VLAN Routing implementation treats the ISL and 802.10 protocols as encapsulation types. On a physical router interface that receives and transmits VLAN packets, you can select an arbitrary subinterface and map it to the particular VLAN “color” embedded within the VLAN header. This mapping allows you to selectively control how LAN traffic is routed or switched outside of its own VLAN domain. In the VLAN routing paradigm, a switched VLAN corresponds to a single routed subnet, and the network address is assigned to the subinterface.

To route a received VLAN packet the Cisco IOS software VLAN switching code first extracts the VLAN ID from the packet header (this is a 10-bit field in the case of ISL and a 4-byte entity known as the security association identifier in the case of IEEE 802.10), then demultiplexes the VLAN ID value into a subinterface of the receiving port. If the VLAN color does not resolve to a subinterface, the Cisco IOS software can transparently bridge the foreign packet natively (without modifying the VLAN header) on the condition that the Cisco IOS software is configured to bridge on the subinterface itself. For VLAN packets that bear an ID corresponding to a configured subinterface, received packets are then classified by protocol type before running the appropriate protocol specific fast switching engine. If the subinterface is assigned to a bridge group then non-routed packets are de-encapsulated before they are bridged. This is termed “fall-back bridging” and is most appropriate for nonroutable traffic types.

In Figure 10, Router A provides inter-VLAN connectivity between multiple Cisco switching platforms where there are three distinct virtual topologies present. For example, for VLAN 300 across the two Catalyst 1200A segments, traffic originating on LAN interface 1 is “tagged” with a VLAN ID of 300 as it is switched onto the FDDI ring. This ID allows the remote Catalyst 1200A to make an intelligent

Cisco IOS Bridging and IBM Networking Configuration Guide

BC-32

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Contents Transparent and SRT Bridging BC-23Integrated Routing and Bridging Transparent Bridging FeaturesBC-24 Bridge-Group Virtual Interface BC-25BC-26 Bridge-Group Virtual Interface in the RouterOther Considerations SRT Bridging FeaturesBC-27 Transparent and SRT Bridging Configuration Task List BC-28As Ieee 802.1D standard, DEC or Vlan bridge Configuring Transparent Bridging and SRT BridgingAssigning Each Network Interface to a Bridge Group BC-29Choosing the OUI for Ethernet Type II Frames Command PurposeTransparently Bridged VLANs for ISL BC-30BC-31 Transparently Bridged VLANs on an Fddi BackboneRouting between ISL VLANs BC-32Same bridge group Specifies a subinterfaceSubinterface with the Vlan BC-33Configuring Fast-Switched Transparent Bridging over ATM Configuring a Subscriber Bridge GroupConfiguring Transparent Bridging over WANs BC-34Defining the Protocols to Bridge Configuring Transparent Bridging over DDRCommand Specifying the Bridging ProtocolConfiguring an Interface for Bridging Configuring Transparent Bridging over Frame RelayDetermining Access for Bridging Fast-Switched Transparent BridgingBridging in a Frame Relay Network with Multicasts Configuring Transparent Bridging over Multiprotocol LapbBridging in a Frame Relay Network with No Multicasts BC-37Specifies IP-to-X.121 mapping Configuring Transparent Bridging over SmdsConfiguring Transparent Bridging over BC-38Specifies a protocol to be routed on a bridge group Configuring Concurrent Routing and BridgingConfiguring Integrated Routing and Bridging BC-39Enabling Integrated Routing and Bridging Configuring InterfacesConfiguring the Bridge-Group Virtual Interface BC-40Configuring Protocols for Routing or Bridging BC-41Disabling IP Routing Configuring Transparent Bridging OptionsBC-42 Enabling Autonomous Bridging Configuring LAT CompressionBC-43 Establishes a multiple spanning-tree domain Establishing Multiple Spanning-Tree DomainsBC-44 Forwarding Multicast Addresses Configuring Bridge Table Aging TimeFiltering Transparently Bridged Packets BC-45Setting Filters at the MAC Layer BC-46Ethernet-ordered MAC address Filters particular MAC-layer station addressesFiltering by Vendor Code BC-47Type Filtering by Protocol TypeBC-48 Interface Defining and Applying Extended Access ListsConfiguration mode BC-49BC-50 Enabling LAT Group Code Service Filtering Filtering LAT Service AnnouncementsBC-51 Adjusting Spanning-Tree Parameters BC-52Adjusting Bpdu Intervals Setting the Bridge PrioritySetting an Interface Priority Assigning Path CostsDisabling the Spanning Tree on an Interface Adjusting the Interval between Hello BPDUsDefining the Forward Delay Interval Defining the Maximum Idle IntervalBC-55 Configuring the PA-12E/2FE Port Adapter BC-56Monitoring and Maintaining the PA-12E/2FE Port Adapter BC-57BC-58 BC-59 Configuring Circuit Groups BC-60Distributes base load on the source MAC address only Configuring Constrained Multicast FloodingConfigures a transmission pause interval BC-61BC-62 Basic Bridging Example BC-63Concurrent Routing and Bridging Example BC-64Basic Integrated Routing and Bridging Example BC-65Complex Integrated Routing and Bridging Example BC-66Transparently Bridged VLANs Configuration Example BC-67Router Two Router OneBC-68 Router Three BC-69Ethernet-to-FDDI Transparent Bridging Example Routing between VLANs Configuration ExampleBC-70 Router/Bridge in Building Ethernet Bridging ExampleBC-71 SRT Bridging Example BC-72Multicast or Broadcast Packets Bridging Example Configuration for the New York City RouterConfiguration for the Thule, Greenland Router BC-73Transparent Bridging Example Configuration for BridgeBC-74 Bridging in a Frame Relay Network with No Multicasts Frame Relay Transparent Bridging ExamplesBC-75 Bridging in a Frame Relay Network with Multicasts Transparent Bridging over Multiprotocol Lapb ExampleBC-76 Transparent Bridging over DDR Examples BC-77Complex Transparent Bridging Network Topology Example Fast-Switched Transparent Bridging over Smds ExampleBC-78 BC-79 Bridged Subnetworks with DomainsConfiguration for Router a BC-80Configuration for Router D Configuration for Router BConfiguration for Router C BC-81ATM Subscriber Ports, ATM Trunk Example Fast Ethernet Subscriber Port, Frame Relay Trunk ExampleBC-82 BC-83 Configuration of IRB for PA-12E/2FE Port Adapter Example BC-84

BC-23 specifications

Cisco Systems has long been a leader in the networking industry, and its BC-23 model exemplifies the company's commitment to innovation and performance. Aimed at enhancing business operations, the BC-23 is tailored for organizations looking for robust solutions that support their digital transformation efforts.

One of the standout features of the Cisco BC-23 is its advanced networking capabilities. It supports high-speed data transmission, enabling seamless communication across networks. With multi-gigabit Ethernet ports, the BC-23 facilitates faster data rates, accommodating the increasing bandwidth demands of modern applications. This feature is particularly beneficial for businesses that rely heavily on cloud services, video conferencing, and data-heavy applications.

Security is a top priority, and the Cisco BC-23 incorporates cutting-edge security measures. Integrated threat detection and prevention systems help safeguard sensitive data from cyber threats. Additionally, the device supports secure access protocols, ensuring that only authorized users can connect to the network. This multi-layered security approach not only protects the network infrastructure but also secures the integrity of the data being transmitted.

Another significant characteristic of the BC-23 is its support for software-defined networking (SDN). This technology allows businesses to manage their networks through centralized software applications, facilitating real-time adjustments and optimizations. The flexibility afforded by SDN is especially advantageous in dynamic environments where network demands can shift rapidly.

The Cisco BC-23 also offers enhanced management features, allowing IT teams to monitor network performance and analytics effectively. This visibility into network operations enables organizations to identify potential issues before they escalate, minimizing downtime and keeping business processes smooth.

Furthermore, the BC-23 is designed for scalability. As organizations grow, their networking needs evolve, and the BC-23 can easily adapt to these changes. Businesses can add additional devices and capabilities without the need for a complete overhaul of their existing infrastructure.

With its combination of speed, security, and scalability, the Cisco Systems BC-23 is an invaluable asset for modern businesses. It stands out not just as a networking device but as a comprehensive solution that meets the demands of today's fast-paced, technology-driven environment. As companies continue to leverage digital tools for growth and efficiency, the BC-23 will undoubtedly play a significant role in their success.
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