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Table Of Contents
Prerequisites for Hot Standby MAC Address
Restrictions for Hot Standby MAC Address
Information About Hot Standby MAC Address
Multiple CIPs or CPAs in the Ethernet Environment
Behavior of HSMA Protocol Between Two HSMA Peers
Active Service Access Points on the Adapter
Benefits of Hot Standby MAC Address
How to Configure Hot Standby MAC Address Functionality
Configuring the Active Adapter
Configuring the HSMA Control Adapter
Configuration Examples for Hot Standby MAC Address
Hot Standby MAC Address
The Hot Standby MAC Address (HSMA) feature achieves redundancy and fault tolerance and avoids a single point of failure of Cisco Channel Interface Processors (CIPs) or Channel Port Adapters (CPAs). This feature also ensures that multiple devices on the Ethernet can have a common MAC address.
Feature History for the Hot Standby MAC Address
Cisco IOS Releases 12.2(16), 12.3(1), and CMCC Ucode Release 28-14
This feature was introduced.
Finding Support Information for Platforms and Cisco IOS Software Images
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Contents
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Prerequisites for Hot Standby MAC Address
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Prerequisites for Hot Standby MAC Address
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Restrictions for Hot Standby MAC Address
HSMA is used for IBM mainframe application only.
Information About Hot Standby MAC Address
To configure the Hot Standby MAC Address feature on a CIP or CPA, you should understand the following concepts:
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Multiple CIPs or CPAs in the Ethernet Environment
When you migrate from Token Ring and/or FDDI to Ethernet, you lose the ability to have multiple CIPs and CPAs in the network with duplicate MAC addresses. Under Token Ring and FDDI, the physical medium format provides a means of distinguishing among the common multiple MAC addresses by way of the routing information field (RIF). Ethernet does not provide this RIF in its definition. When you use duplicate MAC addresses in an Ethernet environment, confusion occurs in the switch tables, resulting in link loss.
Behavior of HSMA Protocol Between Two HSMA Peers
An HSMA environment consists of two control adapters working together as peers. The adapters can be either two CIPs, two CPAs, or one CIP and one CPA. A Cisco CIP or a CPA in an HSMA environment must have a peer to be effective. Peered devices communicate with each other over a Logical Link Control (LLC) session between the two control adapters. Each peer monitors the other and negotiates roles in the event of a race condition. The LLC stack is enhanced to allow HSMA also to control the virtual adapters. When a device negotiates to be a standby device, it disables the virtual adapter on the CIP or CPA. When disabled, the virtual adapter does not transmit any MAC frame with the HSMA MAC adapter's source address. Only the active device utilizes the HSMA MAC adapter address owing to the restriction that Ethernet switches enforce. If both devices advertise the address at the same time, unpredictable results ensue.
A new HSMA protocol facilitates communication between two HSMA peers. The HSMA protocol data is carried over the LLC session between the peers. The exchange of information between the two peers decides which state (active state or inactive state) the two devices are in. When there is a loss of communication, the devices assume that their partner has been taken offline either by a network error or because of a network outage, and the local peer goes into the active state.
Active Service Access Points on the Adapter
HSMA monitors the state of the local Extended Communications Adapter (XCA) device by checking for active service access points (SAPs) periodically. When there are open SAPs on the adapter, the adapter is considered to be in an XCA active state; otherwise the adapter is considered to be in an XCA inactive state. Therefore, you should never configure an adapter that is used by the HSMA stack to be used by any other feature on the CIP or CPA; such a configuration might cause HSMA to see a false positive. By monitoring the XCA device, host operators force a device change by forcing all the XCA devices on that adapter to become inactive.
Benefits of Hot Standby MAC Address
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How to Configure Hot Standby MAC Address Functionality
This section contains the following procedures:
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Configuring the Active Adapter
Use this task to configure the active HSMA adapter.
SUMMARY STEPS
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DETAILED STEPS
Configuring the HSMA Control Adapter
Use this task to configure the HSMA control adapter.
SUMMARY STEPS
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DETAILED STEPS
Tuning HSMA
Use this task to fine-tune the HSMA configuration.
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DETAILED STEPS
Configuration Examples for Hot Standby MAC Address
This section provides the following configuration examples:
Figure 1 shows the HSMA network topology.
Figure 1 HSMA Network Topology
HSMA on Router A: Example
The following example configures HSMA on Router A to work with the HSMA configuration on Router B. To see the corresponding configuration on Router B, see the section "HSMA on Router B: Example."
source-bridge ring-group 100source-bridge transparent 100 1 1 1!interface GigabitEthernet 1/0/0bridge-group 1!interface Channel 2/0csna 0150 00!interface Channel1/0csna 0190 09lan TokenRing 20source-bridge 310 3 100! This is the active adapter.adapter 9 4043.1313.9009 hsma-partner 4043.3333.001alan TokenRing 26source-bridge 319 9 100adapter 26 4043.1111.001a! This is the HSMA control adapter.hsma enable!bridge 1 protocol ieeeHSMA on Router B: Example
The following example configures HSMA on Router B to work with the HSMA configuration on Router A. To see the corresponding configuration on Router A, see the section "HSMA on Router A: Example."
source-bridge ring-group 100source-bridge transparent 100 1 1 1!interface GigabitEthernet 1/0/0bridge-group 1!interface Channel 2/0csna 0150 00!interface Channel3/0lan TokenRing 23source-bridge 330 3 100adapter 9 4043.1313.9009 hsma-partner 4043.1111.001alan TokenRing 31source-bridge 339 9 100adapter 26 4043.3333.001ahsma enable!bridge 1 protocol ieeeAdditional References
The following sections provide references related to the Hot Standby MAC Address.
Related Documents
Bridging and IBM networking
Cisco IOS Bridging and IBM Networking Configuration Guide, Release 12.3
Bridging and IBM networking
Cisco IOS Bridging and IBM Networking Command Reference, Volume 1 of 2: Bridging, Release 12.3
Bridging and IBM networking
Cisco IOS Bridging and IBM Networking Command Reference, Volume 2 of 2: IBM Networking, Release 12.3
Channel port adapters
PA-4C-E 1-Port High-Performance ESCON Channel Port Adapter Installation and Configuration
Standards
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
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MIBs
RFCs
No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.
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Technical Assistance
Command Reference
This section documents new and modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.3 command reference publications.
Modified Commands
New Commands
adapter
To configure internal adapters, use the adapter command in internal LAN interface configuration submode. To remove an internal adapter, use the no form of this command.
adapter adapter-number [mac-address] [hsma-partner hsma-mac-address]
no adapter adapter-number [mac-address]
Syntax Description
Defaults
No default behavior or values
Command Modes
Internal LAN interface configuration
Command History
11.0
This command was introduced.
12.3(3)
The hsma-partner keyword and hsma-mac-address argument were added.
Usage Guidelines
This command is valid only on the virtual channel interface. Internal adapters are used to provide LAN gateway MAC addresses for the following CMCC adapter features: CSNA, Cisco Multipath Channel (CMPC), and TN3270 Server.
Up to 18 internal adapters can be configured on a CMCC adapter. Internal adapters are configured on internal LANs. The only limit to the number of internal adapters that you can configure on a single internal LAN is the limit of up to 18 total internal adapters per CMCC.
When an internal adapter configuration command is removed or an existing internal adapter is modified, the mac-address parameter is not required. In internal adapter configuration mode, the router prompt appears as follows:
router(cfg-adap-type n-m)#In this syntax, type is the internal LAN type, n is the LAN ID, and m is the adapter number.
HSMA is designed to allow redundant CMCC internal adapter MAC addresses in an Ethernet environment. Communication between the HSMA control adapters is used to ensure that only one of the adapters is active at a time.
Examples
The following example shows how to configure internal adapters 3 and 4 (with their corresponding MAC addresses) on the internal Token Ring LAN number 20, and internal adapter 1 on the internal Token Ring LAN number 10:
interface channel 1/2lan tokenring 20adapter 3 4000.7500.0003adapter 4 4000.7500.0004lan tokenring 10source-bridge 100 1 100adapter 1 4000.7500.1111The following example shows how to configure internal adapter 9 to communicate with the HSMA partner at the MAC address 4043.3333.001a:
interface Channel1/2lan TokenRing 20source-bridge 310 3 100adapter 9 4043.1313.9009 hsma-partner 4043.3333.001alan TokenRing 20source-bridge 319 9 100adapter 26 4043.1111.001ahsma enableRelated Commands
hsma control-sap
To override the default control service access point (SAP) for (hot standby MAC address) HSMA peer communications, use the hsma control-sap command in control adapter configuration mode. To restore the default SAP for peer communications, use the no form of this command.
hsma control-sap sap-address
no hsma control-sap sap-address
Syntax Description
sap-address
SAP address used by the HSMA protocol on the control adapter. This is a hexadecimal value. The allowed range is from 0x4 to 0xFC, and the default is 0xEC.
Defaults
The default SAP address, 0xEC, is used.
Command Modes
Control adapter configuration
Command History
Usage Guidelines
This command allows you to override the default control SAP used for HSMA peer communications. The same value must be configured for both HSMA peers or they will not be able to communicate. This command is valid only on the control adapter.
When the hsma control-sap command is changed, it will take effect only after you restart the interface by using the shutdown and no shutdown commands.
Examples
The following example configures the SAP address E8 on control adapter 26:
interface Channel3/0csna 0190 09lan TokenRing 23source-bridge 330 3 100adapter 9 4043.1313.9009 hsma-partner 4043.1111.001alan TokenRing 31source-bridge 339 9 100adapter 26 4043.3333.001ahsma enablehsma control-sap E8hsma dead-interval
To configure the time interval during which at least one hello packet must be received from the peer (hot standby MAC address) HSMA adapter or else the router declares that neighbor down, use the hsma dead-interval command in peered adapter configuration mode. To restore the default value, use the no form of this command.
hsma dead-interval time-interval
no hsma dead-interval time-interval
Syntax Description
time-interval
Time interval used by the HSMA protocol between the control and peered HSMA adapters. Range: 3 to 180. Default: 10.
Defaults
The time interval is set to the default value of 10 seconds.
Command Modes
Peered adapter configuration
Command History
Examples
The following example configures the time interval on adapter 26 to be 8 seconds:
interface Channel1/0load-interval 30csna 0190 09lan TokenRing 20source-bridge 310 3 100adapter 9 4043.1313.9009 hsma-partner 4043.3333.001ahsma dead-interval 8lan TokenRing 26source-bridge 319 9 100adapter 26 4043.1111.001ahsma enablehsma enable
To enable (hot standby MAC address) HSMA on an adapter, use the hsma enable command in control adapter configuration mode. To disable HSMA, use the no form of this command.
hsma enable
no hsma enable
Syntax Description
This command has no keywords or arguments.
Defaults
HSMA is disabled.
Command Modes
Control adapter configuration
Command History
Usage Guidelines
The hsma enable command instructs HSMA to use the adapter it is configured on as the control adapter. The control adapter is the adapter that is used to send and receive hello updates. HSMA is not enabled on the router until a control adapter is specified by the hsma enable command. The no form of this command is not valid unless all of the HSMA partners have been removed; similarly, the adapter context itself may not be removed unless all of the HSMA partners have been removed.
This command is only valid on the control adapter.
The control adapter can be configured under any LAN Token Ring adapter.
Examples
The following example enables HSMA on control adapter 26:
interface Channel1/0lan TokenRing 20source-bridge 310 3 100adapter 9 4043.1313.9009 hsma-partner 4043.3333.001alan TokenRing 26source-bridge 319 9 100adapter 26 4043.1111.001ahsma enablehsma hello-interval
To configure the time interval between hello messages between the peered (hot standby MAC address) HSMA Cisco Channel Interface Processors (CIPs) or Channel Port Adapters (CPAs), use the hsma hello-interval command in peered adapter configuration mode. To restore the default value, use the no form of this command.
hsma hello-interval time-interval
no hsma hello-interval time-interval
Syntax Description
time-interval
Time interval, in seconds, used by the HSMA protocol between the peered HSMA CIP or CPAs. Range: 1 to 60. Default: 3.
Defaults
The time interval is set to the default value of 3 seconds.
Command Modes
Peered adapter configuration
Command History
Usage Guidelines
The hsma hello-interval is the time interval between hello messages that pass between the peered HSMA CIP or CPAs. The control adapter in the enabled mode sends hello messages to the peered adapter after every 2 seconds.
Examples
The following example configures the interval between hello messages on adapter 26 to be 2 seconds:
interface Channel1/0csna 0190 09lan TokenRing 20source-bridge 310 3 100adapter 9 4043.1313.9009 hsma-partner 4043.3333.001ahsma hello-interval 2lan TokenRing 26source-bridge 319 9 100adapter 26 4043.1111.001ahsma enablehsma preferred
To assign priority to a peer as a control adapter, use the hsma preferred command in peered adapter configuration mode. To allow priority to be set without configuring a peer, use the no form of this command.
hsma preferred
no hsma preferred
Syntax Description
This command has no keywords or arguments.
Defaults
Disabled
Command Modes
Peered adapter configuration
Command History
Usage Guidelines
The hsma preferred command is used in situations when both HSMA peers are becoming active at the same time or both were active because of an interruption of communication between the control adapters. In such situations, the adapter with the hsma preferred command configured becomes the active adapter, and the other adapter is disabled. Sessions that are connected to the disabled adapter will be dropped. If the hsma preferred command is not configured on either peer, the control adapter with the higher MAC address is used.
Examples
The following example disables adapter 9 as the HSMA adapter and enables adapter 26 as the active HSMA adapter:
interface Channel1/0csna 0190 09lan TokenRing 20source-bridge 310 3 100adapter 9 4043.1313.9009 hsma-partner 4043.3333.001ahsma preferredhsma shutdownlan TokenRing 26source-bridge 319 9 100adapter 26 4043.1111.001ahsma enablehsma shutdown
To stop (hot standby MAC address) HSMA on an adapter and hence enable the partner adapter, use the hsma shutdown command. To restart the HSMA adapter, use the no form of this command.
hsma shutdown
no hsma shutdown
Syntax Description
This command has no keywords or arguments.
Defaults
HSMA is not shut down.
Command Modes
Peered adapter configuration
Command History
Usage Guidelines
Use the hsma shutdown command when you wish to force the other adapter of a pair to become active.
Examples
The following example disables adapter 9 as the HSMA adapter and enables adapter 26 as the active HSMA adapter:
interface Channel1/0csna 0190 09lan TokenRing 20source-bridge 310 3 100adapter 9 4043.1313.9009 hsma-partner 4043.3333.001ahsma preferredhsma shutdownlan TokenRing 26source-bridge 319 9 100adapter 26 4043.1111.001ahsma enableshow extended channel hsma
To display hot standby MAC address (HSMA) information, use the show access-lists hardware command in privileged EXEC mode.
show extended channel slot:port hsma
Syntax Description
Defaults
There are no defaults.
Command Modes
Privileged EXEC
Command History
Examples
The following example shows sample output of the show extended channel hsma command:
LC-Slot2# show extended channel 1/0 hsmaHSMA information for Channel1/0:Control adapter:LAN Token-26Adapter 26MAC Address 4043.1111.001aHSMA peers for this control adapter:Hot Standby HSMA-Partner LinkLAN Adapter Mac Address Mac Address State========================================================Token 20 09 4043.1313.9009 4043.3333.001a UPControl Sap: EC(configured)(E8 on next restart)Peer State : ActiveLocal State: Standby (Preferred)Open Stations: 1Open SAPs: 1XCA Query Interval: 30 seconds.Hello Interval : 2 seconds.Dead Interval : 8 seconds.Table 1 describes the significant fields shown in the display.
Copyright © 2005 Cisco Systems, Inc. All rights reserved.
