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LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series) First Published: 2017-07-31 Americas Headquarters Cisco Systems, Inc. 170 West Tasman Drive San Jose, CA 95134-1706 http://www.cisco.com Tel: 408 526-4000 800 553-NETS (6387) Fax: 408 527-0883...
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Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks . Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company.
ITU-T G.8032 Ethernet Ring Protection Switching Functionality R-APS Control Messages CFM Protocols and Link Failures G.8032 Ring-Supported Commands and Functionality G.8032 ERP Timers Protection Switching Functionality in a Single Link Failure and Recovery LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
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Blocking State Listening State Learning State Forwarding State Disabled State How a Switch or Port Becomes the Root Switch or Root Port Spanning Tree and Redundant Connectivity LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
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Configuring the Switch Priority of a VLAN Configuring Spanning-Tree Timers Configuring the Hello Time Configuring the Forwarding-Delay Time for a VLAN Configuring the Maximum-Aging Time for a VLAN Displaying the Spanning-Tree Status LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
Information About the UDLD Protocol UDLD Overview The Cisco-proprietary UDLD protocol allows the devices connected through fiber optic or copper (for example, Category 5 cabling) Ethernet cables that are connected to the LAN ports to monitor the physical configuration of the cables and detect whether a unidirectional link exists. When a unidirectional link is detected, the UDLD shuts down the affected LAN port and alerts the corresponding user, because unidirectional links cause a variety of problems, including spanning tree topology loops.
UDLD neighbor relationship established stops receiving the UDLD packets. The UDLD tries to re-establish the connection with the neighbor; the port is disabled after eight failed retries. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
UDLD mode. When UDLD is in normal mode, the link might be considered undetermined and might not be shut down. When UDLD is in LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
Use the no form of this command to disable the UDLD on a non fiber-optic LAN port. Step 5 Returns to privileged EXEC mode. Example: Router# end LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
Ring Protection Link (RPL). A ring link is bound by two adjacent Ethernet ring nodes and a port for a ring link (also known as a ring port). There must be at least two Ethernet ring nodes in a Ethernet ring. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
R-APS Signal Failure (R-APS SF) message in both directions of the nodes adjacent to the failed link, after the nodes have blocked the port facing the failed link. On obtaining this message, the RPL owner unblocks the RPL port. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
VLANs can be configured under only one instance. They cannot overlap multiple instances. Otherwise, data traffic or Ring Automatic Protection Switching (R-APS) messages may cross logical rings, which is not desirable. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
The default time interval is 0 seconds; the time interval ranges from 0 to 10 seconds. Faults are reported to the ring protection mechanism only if this timer expires. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
4 Ethernet ring nodes C and D start sending Ring Automatic Protection Switching (R-APS) SF messages periodically along with the (node ID and bidirectional path-protected ring (BPR) identifier pair) on both ring ports while the SF condition persists. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
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Ethernet ring node D receives an R-APS NR message with a higher node ID from Ethernet ring node C, and unblocks its nonfailed ring port. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
• Local switch-to-switch forwarding between two different interfaces • Feature commands—In each EFP, the QoS features or parameters can be changed and the ACL can be updated. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
• G.8032 is supported only on EFP with dot1q, dot1ad, QinQ, or dot1ad-dot1Q encapsulation type. G.8032 is supported only on TEFP with dot1q. Note • G.8032 is not supported on xconnect interface. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
To enable Ethernet Fault Detection (EFD) for a service to achieve fast convergence, complete the following steps Link protection is not supported on the RSP3 Module. Note LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
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Enables link protection globally on the router. Example: Device(config)# link-protection enable Step 5 link-protection group management vlan vlan-id Defines the management VLAN used for link protection. Example: Device(config)# link-protection group management vlan 51 LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
Device(config-ecfm-srv)# efd notify g8032 Step 11 Returns to user EXEC mode. Example: Device(config-ecfm-srv)# end Configuring the Ethernet Protection Ring To configure the Ethernet Protection Ring (EPR), complete the following steps. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
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Example: Device# configure terminal Step 3 ethernet ring g8032 ring-name Specifies the Ethernet ring and enters Ethernet ring port configuration mode. Example: Device(config)# ethernet ring g8032 ring1 LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
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Specifies VLANs that are unprotected by the Ethernet ring protection mechanism. Example: Device(config-erp-ring)# exclusion-list vlan-ids 2 Step 11 open-ring Specifies the Ethernet ring as an open ring. Example: Device(config-erp-ring)# open-ring LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
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• All nodes in the Ethernet ring must be configured with the same level. Device(config-erp-inst-aps)# level 5 Step 19 port0 service instance instance-id Associates APS channel information with port0. Example: Device(config-erp-inst-aps)# port0 service instance 100 LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
Allows topology change notification (TCN) propagation from a source protocol to a destination protocol. Example: • Source and destination protocols vary by platform and release. Device(config)# ethernet tcn-propagation G8032 to G8032 LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
7. show ethernet ring g8032 port status interface [type number] 8. show ethernet ring g8032 configuration [ring-name] instance [instance-id] 9. show ethernet ring g8032 trace {ctrl [ring-name instance instance-id] | sm} 10. end LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
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[type number] Displays Ethernet ring port status information for the interface. Example: Device# show ethernet ring g8032 port status interface gigabitethernet 0/0/1 LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
By default, MSTP is disabled on all interfaces. MSTP need not be enabled explicitly on each interfaces. By turning the global configuration on, it is enabled on all interfaces. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
Sets the name of the MSTP region. Example: Device(config-mstp)# name m1 Step 6 revision revision -number Sets the revision level of the MSTP region. Example: Device(config-mstp)#)revision 1 LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
Example: Router(config)# interface gigabitEthernet 0/0/5 Step 4 Disables the IP address on the interface. no ip address Example: Router (config-if)# no ip address LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
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GigabitEthernet0/0/0 no ip address negotiation auto service instance trunk 10 ethernet encapsulation dot1q 10-20 bridge-domain from-encapsulation service instance 1024 ethernet encapsulation untagged l2protocol peer stp bridge-domain 1024 LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
This chapter describes how to configure the Spanning Tree Protocol (STP) on port-based VLANs on the Cisco router. The router can use the per-VLAN spanning-tree plus (PVST+) protocol based on the IEEE 802.1D standard and Cisco proprietary extensions, or the rapid per-VLAN spanning-tree plus (rapid-PVST+) protocol based on the IEEE 802.1w standard.
The stable, active spanning-tree topology of a switched network is controlled by these elements: • The unique bridge ID (switch priority and MAC address) associated with each VLAN on each switch. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
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LAN is called the designated port. All paths that are not needed to reach the root switch from anywhere in the switched network are placed in the spanning-tree blocking mode. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
• Blocking—The interface does not participate in frame forwarding. • Listening—The first transitional state after the blocking state when the spanning tree determines that the interface should participate in frame forwarding. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
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3 In the learning state, the interface continues to block frame forwarding as the switch learns end-station location information for the forwarding database. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
An interface in the learning state performs these functions: • Discards frames received on the interface • Discards frames switched from another interface for forwarding • Learns addresses • Receives BPDUs LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
However, because of traffic patterns, number of forwarding interfaces, or link types, Switch A might not be the ideal root switch. By increasing the priority (lowering the numerical value) of the ideal switch so that it LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
If the speeds are the same, the port priority and port ID are added together, and spanning tree disables the link with the lowest value. Figure 7: Spanning Tree and Redundant Connectivity LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
The following spanning-tree modes and protocols are supported: • PVST+—This spanning-tree mode is based on the IEEE 802.1D standard and Cisco proprietary extensions. The PVST+ runs on each VLAN on the switch up to the maximum supported, ensuring that each has a loop-free path through the network.
Beginning in privileged EXEC mode, follow these steps to disable spanning-tree on a per-VLAN basis. This procedure is optional. SUMMARY STEPS 1. configure terminal 2. no spanning-tree vlan vlan-id 3. end 4. show spanning-tree vlan vlan-id LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
Extended system ID is enabled Portfast Default is disabled PortFast BPDU Guard Default is disabled Portfast BPDU Filter Default is disabled Loopguard Default is disabled UplinkFast is disabled LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
Beginning in privileged EXEC mode, follow these steps to configure a switch to become the root for the specified VLAN. This procedure is optional. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
. Beginning in privileged EXEC mode, follow these steps to configure a switch to become the secondary root for the specified VLAN. This procedure is optional. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
Beginning in privileged EXEC mode, follow these steps to configure the port priority of a spanning-tree port. This procedure is optional. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
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The show spanning-tree interface interface-id privileged EXEC c ommand displays information only Note if the port is in a link-up operative state. Otherwise, you can use the show running-config interface privileged EXEC command to confirm the configuration. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
For cost, the range is 1 to 200000000; the default value is derived from the media speed of the interface. Step 4 Return to privileged EXEC mode. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
STP port. Configuring the Hello Time You can configure the interval between the generation of configuration messages by the root switch by changing the hello time. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
Configuring the Forwarding-Delay Time for a VLAN Beginning in privileged EXEC mode, follow these steps to configure the forwarding-delay time for a VLAN. This procedure is optional. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
Beginning in privileged EXEC mode, follow these steps to configure the maximum-aging time for a VLAN. This procedure is optional. SUMMARY STEPS 1. configure terminal 2. spanning-tree vlan vlan-id max-age seconds 3. end 4. show spanning-tree vlan vlan-id 5. copy running-config startup-config LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)
You can clear spanning-tree counters by using the clear spanning-tree [interfaceinterface-id ] privileged EXEC command. For information about other keywords for the show spanning-tree privileged EXEC command, see the command reference for this release. LAN Switching Configuration Guide, Cisco IOS XE Everest 16.6.1 (Cisco NCS 4200 Series)