Lan Switch Configuration

SAMBA-Synergy Advanced Multipurpose Bus Arbiter. Located on both the Supervisor and Line Modules. Provides arbitration to the switching bus. Works in either master or slave mode. SAMBA in master mode is located on the Sup and SAMBA in slave mode is on the line module. Master can support 13 line cards and slave can support 48 ports on a single device. Supports broadcast suppression when SAMBA is in slave mode. Counters gather statics.

EARL-Encoded Address Recognition Logic. This is similar in function to the learning bridges or content addressable memory (CAM) used on other systems. Listens and learns MAC addresses. Associates source port, VLAN ID, and MAC address. The EARL stores up to 128,000 addresses. Stores addresses for 300 seconds (default), can configure between 60 to 1200 seconds.

The SwitchProbeTM (Switched Port Analyzer) gives superior network management and the ability to perform protocol analysis from a single location. The SwitchProbe (Switch Port Analyzer) provides the latest technology for monitoring switch-based networks and helps to reduce the cost of managing these networks. It is included with the Catalyst series switches.

VTP is a Layer 2 messaging protocol that maintains VLAN configuration consistency by managing the addition, deletion, and renaming of VLANs on a network-wide basis. VTP minimizes misconfigurations and configuration inconsistencies that can cause several problems, such as duplicate VLAN names, incorrect VLAN-type specifications, and security violations.

Although the first line is the default line, in priority queuing the default is only applied after all other lines have been attempted. All SMTP mail will automatically be given low priority by the second line. Priority queuing is applied to all packets which are received in Ethernet 0. If you wanted this to be applied to all packets received regardless of interface you would need to associate the priority list with each interface using the priority-group command.

Communication among LANE components is ordinarily handled by several types of switched virtual channel circuits (VCCs). Some VCCs are unidirectional; others are bidirectional. Some are point-to-point; others are point-to-multipoint. Control direct VCC--- The LEC, as part of its initialization, sets up a bi-directional point-to-point VCC to the LES for sending or receiving control traffic. The LEC is required to accept control traffic from the LES through this VCC and must maintain the VCC while participating as a member of the emulated LAN. Other VCCs: Control distribute VCC---The LES may optionally set up a unidirectional VCC back to the LEC for distributing control traffic. Whenever an LES cannot resolve an LE_ARP request from an LEC, it forwards the request out the control distribute VCC to all of the clients in the LAN. The control distribute VCC enables information from the LES to be received whenever a new MAC address joins the LAN or whenever the LES cannot resolve an LE_ARP request. Data direct VCC---Once an ATM address has been resolved by a LEC, this bidirectional point-to-point VCC is set up between clients that want to exchange unicast data traffic.
Most client traffic travels via these VCCs. Multicast send VCC---The LEC sets up a unidirectional point-to-point VCC to a multicast server. This VCC is used by the LEC to sends multicast traffic to the BUS for forwarding out the multicast forward VCC. The LEC also sends out unicast data on this VCC until it resolves the ATM address of a destination. Multicast forward VCC---The BUS sets up a unidirectional VCC to the LECs for distributing data from the BUS. This can either be a unidirectional point-to-point or unidirectional point-to-multipoint VCC. Data sent by an LEC over the multicast send VCC is forwarded to all LEC's via the multicast forward VCC. Configure direct VCC---This is a transient VCC which is set up by the LEC to the LECS in order to obtain the LES ATM address which controls a particular LAN that the LEC wishes to join.

Communication among LANE components is ordinarily handled by several types of switched virtual channel circuits (VCCs). Some VCCs are unidirectional; others are bidirectional. Some are point-to-point; others are point-to-multipoint. Control distribute VCC---The LES may optionally set up a unidirectional VCC back to the LEC for distributing control traffic. Whenever an LES cannot resolve an LE_ARP request from an LEC, it forwards the request out the control distribute VCC to all of the clients in the LAN. The control distribute VCC enables information from the LES to be received whenever a new MAC address joins the LAN or whenever the LES cannot resolve an LE_ARP request. Other VCCs: Control direct VCC--- The LEC, as part of its initialization, sets up a bi-directional point-to-point VCC to the LES for sending or receiving control traffic. The LEC is required to accept control traffic from the LES through this VCC and must maintain the VCC while participating as a member of the emulated LAN. Data direct VCC---Once an ATM address has been resolved by a LEC, this bidirectional point-to-point VCC is set up between clients that want to exchange unicast data traffic.
Most client traffic travels via these VCCs. Multicast send VCC---The LEC sets up a unidirectional point-to-point VCC to a multicast server. This VCC is used by the LEC to sends multicast traffic to the BUS for forwarding out the multicast forward VCC. The LEC also sends out unicast data on this VCC until it resolves the ATM address of a destination. Multicast forward VCC---The BUS sets up a unidirectional VCC to the LECs for distributing data from the BUS. This can either be a unidirectional point-to-point or unidirectional point-to-multipoint VCC. Data sent by an LEC over the multicast send VCC is forwarded to all LEC's via the multicast forward VCC. Configure direct VCC---This is a transient VCC which is set up by the LEC to the LECS in order to obtain the LES ATM address which controls a particular LAN that the LEC wishes to join.

Communication among LANE components is ordinarily handled by several types of switched virtual channel circuits (VCCs). Some VCCs are unidirectional; others are bidirectional. Some are point-to-point; others are point-to-multipoint. Data direct VCC---Once an ATM address has been resolved by a LEC, this bidirectional point-to-point VCC is set up between clients that want to exchange unicast data traffic. Most client traffic travels via these VCCs.Control direct VCC--- The LEC, as part of its initialization, sets up a bi-directional point-to-point VCC to the LES for sending or receiving control traffic. The LEC is required to accept control traffic from the LES through this VCC and must maintain the VCC while participating as a member of the emulated LAN.
Other VCCs: Control distribute VCC---The LES may optionally set up a unidirectional VCC back to the LEC for distributing control traffic. Whenever an LES cannot resolve an LE_ARP request from an LEC, it forwards the request out the control distribute VCC to all of the clients in the LAN. The control distribute VCC enables information from the LES to be received whenever a new MAC address joins the LAN or whenever the LES cannot resolve an LE_ARP request. Multicast send VCC---The LEC sets up a unidirectional point-to-point VCC to a multicast server. This VCC is used by the LEC to sends multicast traffic to the BUS for forwarding out the multicast forward VCC. The LEC also sends out unicast data on this VCC until it resolves the ATM address of a destination. Multicast forward VCC---The BUS sets up a unidirectional VCC to the LECs for distributing data from the BUS. This can either be a unidirectional point-to-point or unidirectional point-to-multipoint VCC. Data sent by an LEC over the multicast send VCC is forwarded to all LEC's via the multicast forward VCC. Configure direct VCC---This is a transient VCC which is set up by the LEC to the LECS in order to obtain the LES ATM address which controls a particular LAN that the LEC wishes to join.

Multicast send VCC---The LEC sets up a unidirectional point-to-point VCC to a multicast server. This VCC is used by the LEC to sends multicast traffic to the BUS for forwarding out the multicast forward VCC. The LEC also sends out unicast data on this VCC until it resolves the ATM address of a destination. Other VCCs: Control direct VCC--- The LEC, as part of its initialization, sets up a bi-directional point-to-point VCC to the LES for sending or receiving control traffic. The LEC is required to accept control traffic from the LES through this VCC and must maintain the VCC while participating as a member of the emulated LAN. Control distribute VCC---The LES may optionally set up a unidirectional VCC back to the LEC for distributing control traffic.
Whenever an LES cannot resolve an LE_ARP request from an LEC, it forwards the request out the control distribute VCC to all of the clients in the LAN. The control distribute VCC enables information from the LES to be received whenever a new MAC address joins the LAN or whenever the LES cannot resolve an LE_ARP request. Data direct VCC---Once an ATM address has been resolved by a LEC, this bidirectional point-to-point VCC is set up between clients that want to exchange unicast data traffic. Most client traffic travels via these VCCs. Multicast forward VCC---The BUS sets up a unidirectional VCC to the LECs for distributing data from the BUS. This can either be a unidirectional point-to-point or unidirectional point-to-multipoint VCC. Data sent by an LEC over the multicast send VCC is forwarded to all LEC's via the multicast forward VCC. Configure direct VCC---This is a transient VCC which is set up by the LEC to the LECS in order to obtain the LES ATM address which controls a particular LAN that the LEC wishes to join.

Multicast forward VCC---The BUS sets up a unidirectional VCC to the LECs for distributing data from the BUS. This can either be a unidirectional point-to-point or unidirectional point-to-multipoint VCC. Data sent by an LEC over the multicast send VCC is forwarded to all LEC's via the multicast forward VCC. Multicast send VCC---The LEC sets up a unidirectional point-to-point VCC to a multicast server. This VCC is used by the LEC to sends multicast traffic to the BUS for forwarding out the multicast forward VCC. The LEC also sends out unicast data on this VCC until it resolves the ATM address of a destination. Other VCCs: Control direct VCC--- The LEC, as part of its initialization, sets up a bi-directional point-to-point VCC to the LES for sending or receiving control traffic.
The LEC is required to accept control traffic from the LES through this VCC and must maintain the VCC while participating as a member of the emulated LAN. Control distribute VCC---The LES may optionally set up a unidirectional VCC back to the LEC for distributing control traffic. Whenever an LES cannot resolve an LE_ARP request from an LEC, it forwards the request out the control distribute VCC to all of the clients in the LAN. The control distribute VCC enables information from the LES to be received whenever a new MAC address joins the LAN or whenever the LES cannot resolve an LE_ARP request. Data direct VCC---Once an ATM address has been resolved by a LEC, this bidirectional point-to-point VCC is set up between clients that want to exchange unicast data traffic. Most client traffic travels via these VCCs. Configure direct VCC---This is a transient VCC which is set up by the LEC to the LECS in order to obtain the LES ATM address which controls a particular LAN that the LEC wishes to join.

Configure direct VCC---This is a transient VCC which is set up by the LEC to the LECS in order to obtain the LES ATM address which controls a particular LAN that the LEC wishes to join. Other VCCs: Control direct VCC--- The LEC, as part of its initialization, sets up a bi-directional point-to-point VCC to the LES for sending or receiving control traffic. The LEC is required to accept control traffic from the LES through this VCC and must maintain the VCC while participating as a member of the emulated LAN. Control distribute VCC---The LES may optionally set up a unidirectional VCC back to the LEC for distributing control traffic. Whenever an LES cannot resolve an LE_ARP request from an LEC, it forwards the request out the control distribute VCC to all of the clients in the LAN. The control distribute VCC enables information from the LES to be received whenever a new MAC address joins the LAN or whenever the LES cannot resolve an LE_ARP request. Data direct VCC---Once an ATM address has been resolved by a LEC, this bidirectional point-to-point VCC is set up between clients that want to exchange unicast data traffic.
Most client traffic travels via these VCCs. Multicast send VCC---The LEC sets up a unidirectional point-to-point VCC to a multicast server. This VCC is used by the LEC to sends multicast traffic to the BUS for forwarding out the multicast forward VCC. The LEC also sends out unicast data on this VCC until it resolves the ATM address of a destination. Multicast forward VCC---The BUS sets up a unidirectional VCC to the LECs for distributing data from the BUS. This can either be a unidirectional point-to-point or unidirectional point-to-multipoint VCC. Data sent by an LEC over the multicast send VCC is forwarded to all LEC's via the multicast forward VCC.

VTP client---In this mode, VTP clients behave like VTP servers, but you cannot create, change, or delete VLANs on a VTP client. In VTP client mode, VLAN configurations are not saved in nonvolatile memory. VTP server---In this mode, you can create, modify, and delete VLANs and specify other configuration parameters (such as VTP version) for the entire VTP domain. VTP servers advertise their VLAN configurations to other switches in the same VTP domain and synchronize their VLAN configurations with other switches based on advertisements received over trunk links. In VTP server mode, VLAN configurations are saved in nonvolatile memory. VTP server is the default mode. VTP transparent---In this mode, VTP transparent switches do not participate in VTP. A VTP transparent switch does not advertise its VLAN configuration and does not synchronize its VLAN configuration based on received advertisements. However, transparent switches do forward VTP advertisements that they receive from other switches. You can create, modify, and delete VLANs. In VTP transparent mode, VLAN configurations are saved in nonvolatile memory, but they are not advertised to other switches.

To setup a VTP, and configure the current switch as a VTP server execute the following commands: 1. Enter VLAN configuration mode vlan database 2. Configure a VTP administrative-domain name. This can be from 1 to 32 characters long. vtp domain domain-name 3. Configure the switch as a server. vtp server. R

The traffic that remains in the bridge group (the bridged traffic) will be bridged among the bridged interfaces, and the traffic that needs to go out to another network (the routed traffic) will be routed internally to the appropriate output routed interface. (See Figure 3.) An external connection is no longer needed to provide this functionality. For example, all the local-area transport (LAT) traffic is bridged within the bridge group and stays local to the bridged interfaces. The IPX traffic destined f or a different network is routed from the bridged interface to the destination routed interface.
In order to implement the internal routing and bridging functionality, IRB uses a new interface, the bridged virtual interface (BVI), a virtual interface that represents the whole bridge group to the routed world. Instead of allowing every bridged interface of the same bridge group to have a unique path to the routed interfaces, there is only one BVI per bridge group, and the BVI represents all the interfaces within that bridge group. Bridging occurs within the bridge group, so bridged traffic has no need for the BVI. The interface number of the BVI is the same number as the bridge group it represents, creating a link between the two. For example, BVI 1 relates to bridge group 1. When configuring an Ethernet interface to map to the BVI, you need to configure the bridge group number in the Ethernet interface and create a BVI to match the bridge group. The router will create the connection between the Ethernet interface and the BVI. If three Ethernet interfaces belong to the same bridge group, they use the same BVI to route traffic. IRB routes through the BVI and bridges within the bridge group. The configurations later in this paper show the mapping between physical interfaces, bridge groups, and the BVIs.

The LANE server for an emulated LAN is the control center. It provides joining, address resolution, and address registration services to the LANE clients in that emulated LAN. Clients can register destination unicast and multicast MAC addresses with the LANE server. The LANE server also handles LANE ARP (LE ARP) requests and responses. LANE configuration server (LECS)---A server that assigns individual clients to particular emulated LANs by directing them to the LES that corresponds to the emulated LAN. The LECS maintains a database of LANE client ATM or MAC addresses and their emulated LANs. An LECS can serve multiple emulated LANs, but there must be one LECS configured for each LANE cloud. The LECS can also be used for security by restricting ELAN membership to certain LECs based on their MAC addresses. Broadcast-and-unknown server (BUS)---A server that floods unknown destination traffic and forwards multicast and broadcast traffic to clients within an emulated LAN. One Cisco BUS exists per emulated LAN.

LANE configuration server (LECS)---A server that assigns individual clients to particular emulated LANs by directing them to the LES that corresponds to the emulated LAN. The LECS maintains a database of LANE client ATM or MAC addresses and their emulated LANs. An LECS can serve multiple emulated LANs, but there must be one LECS configured for each LANE cloud. The LECS can also be used for security by restricting ELAN membership to certain LECs based on their MAC addresses. LANE server (LES)---A server that provides a registration facility for clients to join the emulated LAN. Each emulated LAN has one Cisco LES, which handles LAN Emulation Address Resolution Protocol (LE_ARP) requests and maintains a list or look-up table of LAN destination MAC addresses. Broadcast-and-unknown server (BUS)---A server that floods unknown destination traffic and forwards multicast and broadcast traffic to clients within an emulated LAN. One Cisco BUS exists per emulated LAN.

In the Catalyst family of switches, a virtual LAN (VLAN) is a logical group of end stations, independent of physical location, with a common set of requirements. Currently, the Catalyst switches support a port-centric VLAN configuration. The VLAN number is only significant to the Catalyst family of switches. On an ATM network, an emulated LAN is called an ELAN and is designated by a name. You can configure some ELANs from a router and some from a Catalyst switch. You can also configure ELANs with unrestricted membership and some with restricted membership. You can also configure a default ELAN for LECs that do not specify an ELAN name during the join request. To create a VLAN that spans multiple Catalyst switches on an ATM network, you must assign the VLAN on each Catalyst switch to the same ELAN. Use the lane client ethernet vlan_num elan_name command to link the VLAN number with the ELAN name. You must use a router to allow communication between two or more ELANs, whether they are on the same or different Catalyst switches.

The VIP is a new interface processor for use with the Cisco 7000 series and Cisco 7500 series routers. The VIP uses a single motherboard with up to two port adapters. The VIP port adapters provide the individual LAN, WAN, or LAN/WAN interface ports.

Netflow switching supports the ability to capture accounting statistics for a wide variety of purposes such as network analysis, planning, accounting, and billing.

The VIP hardware can be configured for NetFlow switching, a high-performance feature that identifies initiation of traffic flow between internet endpoints, caches information about the flow, and uses this cache for high-speed switching of subsequent packets within the identified stream. NetFlow switching is faster than the default optimum fast-switching on Cisco 7507 and 7513 platforms when extended access lists are configured. When the RSP or VIP is flow switching, it uses a flow cache instead of a destination network cache to switch IP packets. The flow cache uses source and destination network address, protocol, and source and destination port numbers to distinguish entries.

Version 1 was the initial release, version 5 was a later enhancement to add Border Gateway Protocol and flow sequence number. Version 2 through 4 were not released. NetFlow uses UDP datagrams, which a sequence number for sanity checking.

Although having fast switching on the same ip interface is generally not recommended (because it may interfere with redirection) it is useful when you have a partially meshed media such as frame relay.

Fast switching is enabled by default on all interfaces that support it. Appletalk, Banyan, DecNet, IPX, IOS CLNS, XNS all support fast switching.

The Cisco 7500 has an integrated RSP which uses route caching to remember which port(s) a packet should be forwarded to.

Custom Queueing allows you to assign packets to custom queues based on the protocol type or the interface where the packets enter the router. In addition, you can set the default queue for packets which do not match other assignment rules. Queuing occurs when network congestion occurs. When traffic is moving well within the network, packets are sent as they arrive at the interface. With Custom Queuing you can control a percentage of interface bandwidth for specified traffic by creating protocol queue lists and custom queue lists. To define the custom queueing lists, perform the following tasks in global configuration mode:
1. Establish queueing priorities based upon the protocol type. queue-list list-number protocol protocol-name queue-number queue-keyword keyword-value
2. Establish custom queueing based on packets entering from a given interface. queue-list list-number interface interface-type interface-number queue-number
3. Assign a queue number for those packets that do not match any other rule in the custom queue list. queue-list list-number default queue-number.

Switch> enable [ Enter privileged EXEC mode.] Switch# Switch# configure terminal [ Enter global configuration mode] Switch(config)# interface atm 0[.sub_inter#] [Select the multiservice route processor (CPU) subinterface.] Switch(config-if)# [ It's recommended that you configure LECs on subinterfaces (atm 0.1), not main interfaces(atm 0).] Switch(config-if)# lane client-atm-address atm-address-template [ Specify an ATM address (and override the automatic ATM address assigned to the LANE client).] Switch(config-if)# lane client {ethernet | tokenring} [elan-name] [ Configure a LANE client on the specified subinterface.] Switch(config-if)# end Switch#

A routing decision can be based on a variety of information such as link speed, topological distance, and protocol. Depending on the routing protocol routing decisions are made on bandwidth, delay, Reliablity, Loading , MTU.

Optimum switching is similar to fast switching, but is faster. The first packet is copied to packet memory and the destination network or host is found in the optimum-switching cache. The frame is rewritten and sent to the exit interface that services the destination. Subsequent packets for the same destination use the same switching path. The interface processor computes the CRC.

Half duplex: Capability for data transmission in only one direction at a time between a sending station and a receiving station. Full duplex: Capability for simultaneous data transmission between a sending station and a receiving station. Simplex: Capability for data transmission in only one direction between a sending station and a receiving station.

In process switching the first packet is copied to the system buffer. The router looks up the Layer 3 network address in the routing table and initializes the fast-switch cache. The frame is rewritten with the destination address and sent to the exit interface that services that destination. Subsequent packets for that destination are sent by the same switching path. The route processor computes the cyclical redundancy check (CRC).

NMP - Network Management Processor: governs the general control of the hardware, its configuration and diagnostic routines.

All Multimode transceivers have a maximum distance of 1.2 miles (2 kilometers), Source is a LED.

When packets are fast switched, the first packet is copied to packet memory and the destination network or host is found in the fast-switching cache. The frame is rewritten and sent to the exit interface that services the destination. Subsequent packets for the same destination use the same switching path. The interface processor computes the CRC.

EARL -Enhanced Address Recognition Logic: similar to the function of a learning bridge or content addressable memory, responsible for maintaining the contents of the MAC information.

NetFlow switching enables you to collect the data required for flexible and detailed accounting, billing, and chargeback for network and application resource utilization. Accounting data can be collected for both dedicated line and dial-access accounting. NetFlow switching over a foundation of VLAN technologies provides the benefits of switching and routing on the same platforms. NetFlow switching is supported over switched LAN or ATM backbones, allowing scalable inter-VLAN forwarding. NetFlow switching can be deployed at any location in the network as an extension to existing routing infrastructures.

LAN Emulation Client (LEC): A LEC is the entity in an end system that performs data forwarding, address resolution, and other control functions for a single end-system within a single ELAN. A LEC also provides a standard LAN service interface to any higher layer entity that interfaces to the LEC. An ATM NIC or LAN switch interfacing to an ELAN supports a single LEC for each ELAN to which they are connected. An end-system that connects to multiple ELANs (perhaps over the same UNI) will have one LEC per ELAN.

The Catalyst 5500 switch chassis has 13 slots. Slot 1 is for the Supervisor Engine II model which provides switching, local and remote management, and dual Fast Ethernet interfaces. Slot 2 contains an additional redundant Supervisor Engine II in case the first module fails. A failure of the active Supervisor Engine II is detected by the standby module, which takes control of the Supervisor Engine II switching functions. If a redundant Supervisor Engine II is not required, slot 2 is available for any interface module.

Distributed Switching becomes more efficient the closer to the interface the function occurs. In distributed switching, the switching process occurs on VIP and other interface cards that support switching.

On the Catalyst 3000 you may change the password via in-band or out of band management. However if you press ESC-DEL during the boot of the switch you can enter ROM monitor mode where you can clear the password. There is no minimum password, and the password must be same for all switches on a catalyst stack. 7 slots for modules, 40mbs to 700mbps on the backplane. The Catalyst 3000 must have a different password than the Catalyst Stack. If you have forgotten the password, you can delete it by depressing the Sys Req button on the back panel of the Catalyst 3000 for 1 second, releasing it, then selecting Clear Non-Volatile RAM from the menu that appears. You must then re-enter all system configuration information, including reentering the key for the optional Enhanced feature set.

Packet switching approach that streams data through a switch so that the leading edge of a packet exits the switch at the output port before the packet finishes entering the input port. A device using cut-through packet switching reads, processes, and forwards packets as soon as the destination address is looked up and the outgoing port determined. Also known as on-the-fly packet switching. Cut-through with fast frag means that when the port reaches a certain error level the switch goes into store and forward mode to reduce the number of errors which are propagated. Packet-switching technique in which frames are completely processed before being forwarded out the appropriate port. This processing includes calculating the CRC and checking the destination address. In addition, frames must be temporarily stored until network resources (such as an unused link) are available to forward the message.

Only the Catalyst 5500 has full supervisor redundancy with a Supervisor II installed. Supervisor resilience is available only on the 13-slot chassis of the Catalyst 5500 switch. No software commands are needed to enable this functionality. You can use the Catalyst 5500 series switch to create a high-speed, fault-tolerant environment that supports mission-critical applications by using a second supervisor module in the chassis of your switch. The second supervisor module takes over in case of the failure of the active supervisor module.
When you use two supervisor modules in the chassis to provide redundancy, the first supervisor module to come up is considered the active module. The second supervisor module remains in standby mode. All network management functions, such as Simple Network Management Protocol (SNMP), command-line interface (CLI) console, Telnet, spanning tree, Cisco Discovery Protocol (CDP), and virtual LAN (VLAN) Trunk Protocol (VTP) take place on the active supervisor module. The Ethernet ports on the standby supervisor module are inactive in the same way that enabled ports on disabled modules are inactive. The console port on the standby supervisor module is also inactive. The redundant supervisor modules operate in the first two slots of the 13-slot chassis. The supervisor modules are hot-swappable, and in the redundant configuration, the system continues to operate with the same configuration after switching over to the redundant supervisor.

PHOENIX ASIC-A gate array ASIC used to connect the switching buses. Available on SUP III. Supports 3.6Gbps crossbar fabric, layer 3 switching support with EARL II, CISCO IOS support.