PDF(21.1 KB) View with Adobe Reader on a variety of devices
Updated:June 5, 2005
Simple Server Redundancy Protocol (SSRP) provides redundancy within an ATM cloud. Before SSRP, redundancy was not possible between the LAN emulation server (LES) and the Broadcast Unknown Server (BUS). When either of these failed, all of the LAN emulation clients (LECs) on this Emulated LAN (ELAN) would go down. They could not come up until the connectivity to the LES and BUS were restored.
With SSRP, it is possible to have more than one LES/BUS running in a LANE cloud. This document will show the configurations of a network with a redundant LES/BUS. The LAN emulation configuration server (LECS) will not be redundant.
The SSRP redundancy feature only works with Cisco LECS and Cisco LES/BUS combinations. You can use third-party LANE clients with SSRP, but third-party LES, BUS and third-party LECS do not support SSRP, proprietary to Cisco. Third-party LECs work in an SSRP environment. LECs can locate the configuration server in an SSRP-enabled network by using the:
Interim Local Management Interface (ILMI).
Well-known network service access point (NSAP) address.
Note: The locations of the various services shown in this document might not be optimal. Before implementing such a configuration in a live network, please review the LANE Design Recommendations.
Hardware support for SSRP is not required since the LEC is not involved. As a result, third party LECs will also be able to benefit from the SSRP.
Below are the software versions for LES/BUS/LECS that support SSRP:
Cisco Catalyst LANE Module version 3.1 and later
Cisco LightStream 1010 Version 11.2 and later
Cisco IOS version 11.2 and later
In this diagram, all three of the devices are running as LECs. The LS1010 ATM switch and the Cisco 7200 router both provide an LES and BUS. The LECS is configured on the LS1010.
Catalyst 5500 LANE Module (LEC Only)
For the LANE client, there is no change in the configuration. Below is the current configuration:
CAT5500 LANE Module (LEC Only)
Current configuration: ! hostname ATM-5500 ! interface Ethernet0 ! interface ATM0 atm preferred phy A atm pvc 1 0 5 qsaal atm pvc 2 0 16 ilmi no atm ilmi-keepalive ! interface ATM0.1 multipoint lane client ethernet 1 admin ! end
7200 (Master LES/BUS + LEC)
For the LES/BUS on the 7200 platform, there are also no configuration changes needed. Below is the current configuration:
7200 (Master LES/BUS + LEC Only)
Current configuration: ! version 12.1 ! interface ATM4/0 no ip address no ip route-cache cef atm pvc 1 0 5 qsaal atm pvc 2 0 16 ilmi no atm ilmi-keepalive ! interface ATM4/0.2 multipoint lane server-bus ethernet admin elan-id 1 ! interface ATM4/0.3 multipoint lane client ethernet admin ! end
LS1010 (LECS, LEC and Backup LES/BUS)
When using SSRP, only the LANE database will need to be modified. Instead of entering only one server ATM address, you can now configure multiple server ATM addresses in the database. Below is the current configuration:
LS1010 (LECS, LEC and Backup LES/BUS)
Current configuration: ! version 12.0 ! atm lecs-address-default 47.0091.8100.0000.0060.3e5a.4501.0060.3e5a.4505.00 1 atm address 47.0091.8100.0000.0060.3e5a.4501.0060.3e5a.4501.00 atm router pnni no aesa embedded-number left-justified node 1 level 56 lowest redistribute atm-static ! ! lane database SSRPConfig name admin server-atm-address 47.00918100000000603E5A4501.0030199AB871.02 name admin server-atm-address 47.00918100000000603E5A4501.00603E5A4503.02 name admin elan-id 1 ! ! interface ATM2/0/0 no ip address no ip directed-broadcast atm maxvp-number 0 lane config auto-config-atm-address lane config database SSRPConfig ! interface ATM2/0/0.1 multipoint no ip directed-broadcast lane client ethernet admin ! interface ATM2/0/0.2 multipoint no ip directed-broadcast lane server-bus ethernet admin elan-id 1 ! end
LAN Emulation Client
The show lane client detail command output is shown below. As you can see, each of the three devices used in the network is aware of only the active LES.
Cat5500 LANE module
ATM#show lane client detail LE Client ATM0.1 ELAN name: admin Admin: up State: operational Client ID: 1 LEC up for 17 minutes 44 seconds ELAN ID: 1 Join Attempt: 10 Known LE Servers: 1 <-- Only one Lan Emulation Server known by the LEC Last Fail Reason: ATM prefix being changed HW Address: 00e0.1410.d830 Type: ethernet Max Frame Size: 1516 VLANID: 1 ATM Address: 47.00918100000000603E5A4501.00E01410D830.01 VCD rxFrames txFrames Type ATM Address 0 0 0 configure 47.00918100000000603E5A4501.00603E5A4505.00
7200#show lane client detail LE Client ATM4/0.3 ELAN name: admin Admin: up State: operational Client ID: 2 LEC up for 48 seconds ELAN ID: 1 Join Attempt: 1 Known LE Servers: 1 <-- Only one LAN Emulation Server known by the LEC HW Address: 0030.199a.b870 Type: ethernet Max Frame Size: 1516 ATM Address: 47.00918100000000603E5A4501.0030199AB870.03 VCD rxFrames txFrames Type ATM Address 0 0 0 configure 47.00918100000000603E5A4501.00603E5A4505.00
LS1010#show lane client detail LE Client ATM2/0/0.1 ELAN name: admin Admin: up State: operational Client ID: 3 LEC up for 6 minutes 20 seconds ELAN ID: 1 Join Attempt: 1 Known LE Servers: 1 <- Only one LAN Emulation Server known by the LEC Last Fail Reason: Locally deactivate HW Address: 0060.3e5a.4502 Type: ethernet Max Frame Size: 1516 ATM Address: 47.00918100000000603E5A4501.00603E5A4502.01 VCD rxFrames txFrames Type ATM Address 0 0 0 configure 47.00918100000000603E5A4501.00603E5A4505.00
The show lane server command displays the status of the LES. As the outputs below show, the 7200 is acting as the Active LES and all three LECs have joined. The backup LES (LS1010) has no clients.
Master LES (7200)
7200#show lane server LE Server ATM4/0.2, Elan name: admin, Admin: up, State: operational Master/Backup: Master, Type: ethernet, Max Frame Size: 1516 locally set elan-id: 1 elan-id obtained from LECS: not set ATM address: 47.00918100000000603E5A4501.0030199AB871.02 LECS used: 47.00918100000000603E5A4501.00603E5A4505.00 connected, vcd 14 control distribute: vcd 16, 3 members, 754 packets <- All 3 LEC have joined the Active LES proxy/ (ST: Init, Conn, Waiting, Adding, Joined, Operational, Reject, Term) lecid ST vcd pkts Hardware Addr ATM Address 1P O 15 752 00e0.1410.d830 47.00918100000000603E5A4501.00E01410D830.01 2P O 32 2 0030.199a.b870 47.00918100000000603E5A4501.0030199AB870.03 3P O 27 2 0060.3e5a.4502 47.00918100000000603E5A4501.00603E5A4502.01
Backup LES (LS1010)
As shown in the output of show lane server on the LS1010, the Backup LES does not have any members and is in Backup state until the active LES fails. It will then begin accepting connections.
LS1010#show lane server LE Server ATM2/0/0.2, Elan name: admin, Admin: up, State: operational Master/Backup: Backup, Type: ethernet, Max Frame Size: 1516 locally set elan-id: 1 elan-id obtained from LECS: 1 ATM address: 47.00918100000000603E5A4501.00603E5A4503.02 LECS used: 47.00918100000000603E5A4501.00603E5A4505.00 connected, vcd 123
LAN Emulation Configuration Server
The show lane config command displays the status of the LECS.
The output below shows that the LECS have set up a VCD to both of the LESs that are configured. The output also indicates which of the two is the active LES.
LS1010#show lane config LE Config Server ATM2/0/0 config table: SSRPConfig Admin: up State: operational LECS Mastership State: active master list of global LECS addresses (7 seconds to update): 47.00918100000000603E5A4501.00603E5A4505.00 <------ me ATM Address of this LECS: 47.00918100000000603E5A4501.00603E5A4505.00 (auto) vcd rxCnt txCnt callingParty 112 1 1 47.00918100000000603E5A4501.0030199AB871.02 LES admin 0 active <-- Primary LES 124 1 1 47.00918100000000603E5A4501.00603E5A4503.02 LES admin 1 backup <--- Backup LES cumulative total number of unrecognized packets received so far: 0 cumulative total number of config requests received so far: 13 cumulative total number of config failures so far: 1 cause of last failure: no configuration culprit for the last failure: 47.00918100000000603E5A4501.00603E5A4503.02
The show lane database command allows you to verify which LANE database has been used for the LECS.
LS1010#show lane database LANE Config Server database table 'SSRPConfig' bound to interface/s: ATM2/0/0 no default elan elan 'admin': un-restricted, elan-id 1, preempts server 47.00918100000000603E5A4501.0030199AB871.02 (prio 0) server 47.00918100000000603E5A4501.00603E5A4503.02 (prio 1)