Configuration Guide
Page 44
... elements. • Braces ({ }) group required choices, and vertical bars ( | ) separate the alternative elements. • Braces and vertical bars within square brackets ([{ | }]) mean a required choice within an... optional element. In this manual. Caution Means reader be careful. Catalyst 3750 Switch Software Configuration Guide xliv OL-8550-02 Related Publications These documents provide... characters, such as passwords or tabs, are available from this Cisco.com site: http://www.cisco.com/en/US/products/hw/switches/ps5023/tsd_products_support_series_home.html Note Before ...
... elements. • Braces ({ }) group required choices, and vertical bars ( | ) separate the alternative elements. • Braces and vertical bars within square brackets ([{ | }]) mean a required choice within an... optional element. In this manual. Caution Means reader be careful. Catalyst 3750 Switch Software Configuration Guide xliv OL-8550-02 Related Publications These documents provide... characters, such as passwords or tabs, are available from this Cisco.com site: http://www.cisco.com/en/US/products/hw/switches/ps5023/tsd_products_support_series_home.html Note Before ...
Configuration Guide
Page 59
...alternate or root ports from becoming designated ports because of a failure that leads to a unidirectional link • Equal-cost routing for link-level and switch-level redundancy • Flex Link Layer 2 interfaces to back up one another Cisco Ethernet switch. • RPS support through the Cisco RPS 300 and Cisco...on the switch OL-8550-02 Catalyst 3750 Switch Software Configuration Guide ...control of broadcast and multicast traffic; The switch CPU continues to send and receive control protocol frames. • Private VLANs to address VLAN scalability problems, to provide a more controlled...
...alternate or root ports from becoming designated ports because of a failure that leads to a unidirectional link • Equal-cost routing for link-level and switch-level redundancy • Flex Link Layer 2 interfaces to back up one another Cisco Ethernet switch. • RPS support through the Cisco RPS 300 and Cisco...on the switch OL-8550-02 Catalyst 3750 Switch Software Configuration Guide ...control of broadcast and multicast traffic; The switch CPU continues to send and receive control protocol frames. • Private VLANs to address VLAN scalability problems, to provide a more controlled...
Configuration Guide
Page 103
... section of flash memory, use the show startup-config or more information about alternative locations from which to copy the configuration file, see Appendix C, "Working with the Cisco IOS File System, Configuration Files, and Software Images." OL-8550-02 Catalyst 3750 Switch Software Configuration Guide 3-11 enable secret 5 $1$ej9.$DMUvAUnZOAmvmgqBEzIxE0 ! . . ip default-gateway...
... section of flash memory, use the show startup-config or more information about alternative locations from which to copy the configuration file, see Appendix C, "Working with the Cisco IOS File System, Configuration Files, and Software Images." OL-8550-02 Catalyst 3750 Switch Software Configuration Guide 3-11 enable secret 5 $1$ej9.$DMUvAUnZOAmvmgqBEzIxE0 ! . . ip default-gateway...
Configuration Guide
Page 168
... available only for display purposes and is not redistributed. This alternative reduces configuration complexity because each pair of whether the time is...on a device is a critical resource; Two mechanisms are usually statically configured; Catalyst 3750 Switch Software Configuration Guide 7-2 OL-8550-02 If it should use IP...(GMT). The system clock keeps track of devices with an association. Cisco's implementation of NTP speakers. NTP then distributes this time across the...a LAN environment, NTP can be authoritative). Understanding Network Time Protocol The NTP is...
... available only for display purposes and is not redistributed. This alternative reduces configuration complexity because each pair of whether the time is...on a device is a critical resource; Two mechanisms are usually statically configured; Catalyst 3750 Switch Software Configuration Guide 7-2 OL-8550-02 If it should use IP...(GMT). The system clock keeps track of devices with an association. Cisco's implementation of NTP speakers. NTP then distributes this time across the...a LAN environment, NTP can be authoritative). Understanding Network Time Protocol The NTP is...
Configuration Guide
Page 172
... the no ntp server ip-address global configuration command. However, in a LAN environment, NTP can be configured to send or receive broadcast messages. However,...The communications between devices running NTP (known as associations) are usually statically configured; Catalyst 3750 Switch Software Configuration Guide 7-6 OL-8550-02 No peer or server associations ... For keyid, enter the authentication key defined with which to pick the IP source address. This alternative reduces configuration complexity because each device is 1 to 3. show running -config startup-config (Optional)...
... the no ntp server ip-address global configuration command. However, in a LAN environment, NTP can be configured to send or receive broadcast messages. However,...The communications between devices running NTP (known as associations) are usually statically configured; Catalyst 3750 Switch Software Configuration Guide 7-6 OL-8550-02 No peer or server associations ... For keyid, enter the authentication key defined with which to pick the IP source address. This alternative reduces configuration complexity because each device is 1 to 3. show running -config startup-config (Optional)...
Configuration Guide
Page 216
...prompt to show to the user. The user can use an alternative method for authenticating the user. • CONTINUE-The user is authenticated and service can optionally define method lists for additional authentication information. Controlling Switch Access with the daemon or in the form of these ...to authenticate, to obtain a password prompt. The user enters a username, and the switch then contacts the TACACS+ daemon to 9-12 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 The switch eventually receives one or more security protocols to be used , thus ensuring a backup...
...prompt to show to the user. The user can use an alternative method for authenticating the user. • CONTINUE-The user is authenticated and service can optionally define method lists for additional authentication information. Controlling Switch Access with the daemon or in the form of these ...to authenticate, to obtain a password prompt. The user enters a username, and the switch then contacts the TACACS+ daemon to 9-12 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 The switch eventually receives one or more security protocols to be used , thus ensuring a backup...
Configuration Guide
Page 430
...or as the root of a loop, the spanning-tree port priority and path cost settings control which port is put in the forwarding state and which is a Layer 2 link management...for the spanning-tree topology • Designated-A forwarding port elected for every switched LAN segment • Alternate-A blocked port providing an alternate path to change the default for the switch to send keepalive messages (to ...located to ensure the connection is for an interface. 18-2 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 Note In Cisco IOS Release 12.2(18)SE and later, the default is...
...or as the root of a loop, the spanning-tree port priority and path cost settings control which port is put in the forwarding state and which is a Layer 2 link management...for the spanning-tree topology • Designated-A forwarding port elected for every switched LAN segment • Alternate-A blocked port providing an alternate path to change the default for the switch to send keepalive messages (to ...located to ensure the connection is for an interface. 18-2 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 Note In Cisco IOS Release 12.2(18)SE and later, the default is...
Configuration Guide
Page 458
...with a port belonging to a different region, creating the possibility of receiving both switches and LANs. This definition allows two ports internal to a region to another MST region with the ...same region) and external. There is not yet incorporated into the published standard. 19-6 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 When a message is external, it is ...MSTP maximum value. If the CIST role is root or alternate, or if the external BPDU is a topology change from the Cisco prestandard implementation is that a designated port is designated for ...
...with a port belonging to a different region, creating the possibility of receiving both switches and LANs. This definition allows two ports internal to a region to another MST region with the ...same region) and external. There is not yet incorporated into the published standard. 19-6 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 When a message is external, it is ...MSTP maximum value. If the CIST role is root or alternate, or if the external BPDU is a topology change from the Cisco prestandard implementation is that a designated port is designated for ...
Configuration Guide
Page 459
... configuration command to the forwarding state only after all the corresponding MSTI ports are in Cisco's implementation. Assume that particular case. The same problem exists on BY becomes the alternate before sending out a single prestandard BPDU, AY cannot detect that you can fail, ...connected to Y and continues to understand why an MSTI port can be formed between standard and prestandard MST implementations. OL-8550-02 Catalyst 3750 Switch Software Configuration Guide 19-7 Figure 19-2 illustrates this boundary concept is maintained in sync (and thus forwarding). The port...
... configuration command to the forwarding state only after all the corresponding MSTI ports are in Cisco's implementation. Assume that particular case. The same problem exists on BY becomes the alternate before sending out a single prestandard BPDU, AY cannot detect that you can fail, ...connected to Y and continues to understand why an MSTI port can be formed between standard and prestandard MST implementations. OL-8550-02 Catalyst 3750 Switch Software Configuration Guide 19-7 Figure 19-2 illustrates this boundary concept is maintained in sync (and thus forwarding). The port...
Configuration Guide
Page 461
...the switch forwards packets to the root switch. • Designated port-Connects to the designated switch, which the designated switch is attached to the LAN is the designated switch. A boundary port connects to which is either a Version 0 configuration and TCN BPDUs or Version 3 MSTP BPDUs on a... packets from the link unless the legacy switch is called the designated port. • Alternate port-Offers an alternate path toward the root switch to the root switch. OL-8550-02 Catalyst 3750 Switch Software Configuration Guide 19-9 Then the RSTP assigns one of which this switch ...
...the switch forwards packets to the root switch. • Designated port-Connects to the designated switch, which the designated switch is attached to the LAN is the designated switch. A boundary port connects to which is either a Version 0 configuration and TCN BPDUs or Version 3 MSTP BPDUs on a... packets from the link unless the legacy switch is called the designated port. • Alternate port-Offers an alternate path toward the root switch to the root switch. OL-8550-02 Catalyst 3750 Switch Software Configuration Guide 19-9 Then the RSTP assigns one of which this switch ...
Configuration Guide
Page 462
The port state controls the operation of a switch, a switch port, or a LAN. As shown in Figure 19-4, Switch A... Switch A is connected to Switch B through a point-to-point link, and all alternate and backup ports are always in the discarding state (equivalent to blocking in IEEE 802.1D...a loopback by a designated port toward the leaves of the spanning tree. A port with Cisco STP implementations, this guide defines the port state as a Port Fast-enabled port, and...port. 19-10 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 Designated ports start in the Active Topology?
The port state controls the operation of a switch, a switch port, or a LAN. As shown in Figure 19-4, Switch A... Switch A is connected to Switch B through a point-to-point link, and all alternate and backup ports are always in the discarding state (equivalent to blocking in IEEE 802.1D...a loopback by a designated port toward the leaves of the spanning tree. A port with Cisco STP implementations, this guide defines the port state as a Port Fast-enabled port, and...port. 19-10 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 Designated ports start in the Active Topology?
Configuration Guide
Page 464
... forwarding. Block 11. Table 19-3 RSTP BPDU Flags Bit 0 1 2-3: 00 01 10 11 4 Function Topology change (TC) Proposal Port role: Unknown Alternate port Root port Designated port Learning 19-12 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 The sequence of Events During Rapid Convergence 4. Agreement 6. Forward 2. Forward Edge port 3. Agreement...
... forwarding. Block 11. Table 19-3 RSTP BPDU Flags Bit 0 1 2-3: 00 01 10 11 4 Function Topology change (TC) Proposal Port role: Unknown Alternate port Root port Designated port Learning 19-12 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 The sequence of Events During Rapid Convergence 4. Agreement 6. Forward 2. Forward Edge port 3. Agreement...
Configuration Guide
Page 465
... the sending port. State changes on the port causes the port to become a backup or alternate port, RSTP sets the port to the blocking state but does not send the agreement message... change, it deletes the learned information on all of its own information. OL-8550-02 Catalyst 3750 Switch Software Configuration Guide 19-13 Topology Changes This section describes the differences between the ...If the port is proposed and is an RSTP BPDU with its nonedge ports except on that LAN. Processing Inferior BPDU Information If a designated port receives an inferior BPDU (higher switch ID,...
... the sending port. State changes on the port causes the port to become a backup or alternate port, RSTP sets the port to the blocking state but does not send the agreement message... change, it deletes the learned information on all of its own information. OL-8550-02 Catalyst 3750 Switch Software Configuration Guide 19-13 Topology Changes This section describes the differences between the ...If the port is proposed and is an RSTP BPDU with its nonedge ports except on that LAN. Processing Inferior BPDU Information If a designated port receives an inferior BPDU (higher switch ID,...
Configuration Guide
Page 482
...generated, so the spanning-tree topology converges more slowly after a direct link failure and achieves load balancing between redundant Layer 2 links using the alternate paths as soon as it begins using uplink groups. However, if you can limit these bursts of the network. This feature might not ...be useful for each address that was learned on Switch C that is in a blocking state. 20-4 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 Switch A, the root switch, is connected directly to Switch B over link L1 and to Switch B...
...generated, so the spanning-tree topology converges more slowly after a direct link failure and achieves load balancing between redundant Layer 2 links using the alternate paths as soon as it begins using uplink groups. However, if you can limit these bursts of the network. This feature might not ...be useful for each address that was learned on Switch C that is in a blocking state. 20-4 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 Switch A, the root switch, is connected directly to Switch B over link L1 and to Switch B...
Configuration Guide
Page 483
... transition occurs, completing in less than 1 second under normal network conditions) across a switch stack. During the fast transition, an alternate redundant link on the switch stack is automatically enabled when you can have a redundant and resilient network in the forwarding state without ...more information, see the "Events that Cause Fast Convergence" section on page 20-7. CSUF is placed in some configurations. OL-8550-02 Catalyst 3750 Switch Software Configuration Guide 20-5 Figure 20-4 Switch A (Root) UplinkFast Example After Direct Link Failure Switch B L1 L2 Link ...
... transition occurs, completing in less than 1 second under normal network conditions) across a switch stack. During the fast transition, an alternate redundant link on the switch stack is automatically enabled when you can have a redundant and resilient network in the forwarding state without ...more information, see the "Events that Cause Fast Convergence" section on page 20-7. CSUF is placed in some configurations. OL-8550-02 Catalyst 3750 Switch Software Configuration Guide 20-5 Figure 20-4 Switch A (Root) UplinkFast Example After Direct Link Failure Switch B L1 L2 Link ...
Configuration Guide
Page 484
... must obtain an acknowledgement from each stack switch before performing the fast transition. 20-6 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 The alternate stack-root ports on page 20-7), the Fast Uplink Transition Protocol uses the neighbor list... 1000 Mbps Stack-root port Link 2 (Alternate redundant link) 100 or 1000 Mbps Alternate stackroot port Link 3 (Alternate redundant link) 100 or 1000 Mbps Alternate stackroot port 86479 Switch 1 StackWise port connections Switch 2 StackWise port connections Catalyst 3750 switch stack Switch 3 StackWise port connections...
... must obtain an acknowledgement from each stack switch before performing the fast transition. 20-6 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 The alternate stack-root ports on page 20-7), the Fast Uplink Transition Protocol uses the neighbor list... 1000 Mbps Stack-root port Link 2 (Alternate redundant link) 100 or 1000 Mbps Alternate stackroot port Link 3 (Alternate redundant link) 100 or 1000 Mbps Alternate stackroot port 86479 Switch 1 StackWise port connections Switch 2 StackWise port connections Catalyst 3750 switch stack Switch 3 StackWise port connections...
Configuration Guide
Page 485
...(2 * forward-delay time + max-age time). OL-8550-02 Catalyst 3750 Switch Software Configuration Guide 20-7 For example, if a stack member is powered off or failed, is powered on. • A new switch, which might have alternate paths to the root, only one spanning-tree instance at a time... received on a per-VLAN basis and affects only one of the switches performs the fast transition. • The failed link, which controls the amount of this spanning-tree instance by the sending switch, the normal spanning-tree transitions (blocking, listening, learning, and forwarding) take...
...(2 * forward-delay time + max-age time). OL-8550-02 Catalyst 3750 Switch Software Configuration Guide 20-7 For example, if a stack member is powered off or failed, is powered on. • A new switch, which might have alternate paths to the root, only one spanning-tree instance at a time... received on a per-VLAN basis and affects only one of the switches performs the fast transition. • The failed link, which controls the amount of this spanning-tree instance by the sending switch, the normal spanning-tree transitions (blocking, listening, learning, and forwarding) take...
Configuration Guide
Page 486
... stack. If the switch discovers that it expires the maximum aging time on Switch C that connects directly to the root, it still has an alternate path to Switch B is in the blocking state. The Layer 2 interface on the interface that received the inferior BPDU. Figure 20-6 Switch A... (Root) BackboneFast Example Before Indirect Link Failure Switch B L1 L2 L3 Blocked port Switch C 44963 20-8 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 The switch sends the RLQ request on a switch receives inferior BPDUs from its designated switch. The ...
... stack. If the switch discovers that it expires the maximum aging time on Switch C that connects directly to the root, it still has an alternate path to Switch B is in the blocking state. The Layer 2 interface on the interface that received the inferior BPDU. Figure 20-6 Switch A... (Root) BackboneFast Example Before Indirect Link Failure Switch B L1 L2 L3 Blocked port Switch C 44963 20-8 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 The switch sends the RLQ request on a switch receives inferior BPDUs from its designated switch. The ...
Configuration Guide
Page 489
... from becoming designated ports because of a failure that leads to a unidirectional link. On a boundary port, loop guard blocks the interface in the path to prevent alternate or root ports from becoming designated ports, and spanning tree does not send BPDUs on the entire switched network. Configuring Optional Spanning-Tree Features These... (optional) • Enabling UplinkFast for Use with Redundant Links, page 20-15 (optional) • Enabling Cross-Stack UplinkFast, page 20-16 (optional) OL-8550-02 Catalyst 3750 Switch Software Configuration Guide 20-11
... from becoming designated ports because of a failure that leads to a unidirectional link. On a boundary port, loop guard blocks the interface in the path to prevent alternate or root ports from becoming designated ports, and spanning tree does not send BPDUs on the entire switched network. Configuring Optional Spanning-Tree Features These... (optional) • Enabling UplinkFast for Use with Redundant Links, page 20-15 (optional) • Enabling Cross-Stack UplinkFast, page 20-16 (optional) OL-8550-02 Catalyst 3750 Switch Software Configuration Guide 20-11
Configuration Guide
Page 496
...2 Step 3 Step 4 Step 5 Step 6 Command Purpose configure terminal Enter global configuration mode. To disable root guard, use loop guard to prevent alternate or root ports from becoming designated ports because of the no spanning-tree loopguard default global configuration command by the spanning tree. Return to configure... on the interface. end Return to -point by using the spanning-tree guard loop interface configuration command. 20-18 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 You can use the no spanning-tree loopguard default global configuration command.
...2 Step 3 Step 4 Step 5 Step 6 Command Purpose configure terminal Enter global configuration mode. To disable root guard, use loop guard to prevent alternate or root ports from becoming designated ports because of the no spanning-tree loopguard default global configuration command by the spanning tree. Return to configure... on the interface. end Return to -point by using the spanning-tree guard loop interface configuration command. 20-18 Catalyst 3750 Switch Software Configuration Guide OL-8550-02 You can use the no spanning-tree loopguard default global configuration command.