This document provides configuration guidance for configuring the Cisco IOS® Server Load Balancer (SLB) feature to distribute large numbers of IP Security (IPsec) tunnels onto a Cisco® 7200/7301 IPsec server farm. The server farm hubs are configured with dynamic Virtual Tunnel Interface (VTI) while the remote spokes can be configured using VTI or crypto maps (supporting single proxy).
1. Audience
This configuration guide is intended to provide best practices and configuration guidelines for Cisco customers, Systems® engineers and customer support engineers.
2. Network Topology
Figure 1. Topology
3. System Components
• Tested version on IPsec hubs: Cisco IOS Software Release 12.4(4)T1
• Tested version on 6500 SLB: Cisco IOS Software Release 12.2(18)SXF
• Tested version on the spokes (crypto maps): Cisco IOS Software Release 12.2(15)T14
4. SLB Configuration
!
! Failure detection mechanism is set to ICMP. Failure to respond to
! three pings will change the status of IPsec server to DOWN
!
ip slb probe PING-PROBE ping
faildetect 3
!
! Define the REAL servers in the server farm. Least loaded server
! will accept new connection. If the server fails, all the connection
! entries will be purged. Max Connections on the servers are set to
! 500 (per server).
!
ip slb serverfarm 7301-FARM
predictor leastconns
failaction purge
probe PING-PROBE
!
real 192.168.1.1
weight 1
maxconns 500
inservice
!
real 192.168.2.1
weight 1
maxconns 500
inservice
!
! Define ESP and ISAKMP (500 and 4500) to be load balanced on these
! servers. To add stickiness between ISAKMP and IPsec, "sticky"
! command is used. IKE and IPsec sessions should never go to two
! different servers. This stickiness should be maintained more than
! the IPsec re-key interval. If the stickiness time is not long
! enough, both the sessions might initially go to same routers but
! when IPsec re-keys after 1 hour, IPsec session can end up on wrong
! server. Similarly idle time is set to a little more than IPsec
! re-key interval to avoid accidental clearance of the connection on
! the SLB. Virtual IP address defined is 200.1.1.1.
ROM: System Bootstrap, Version 12.2(17r)S2, RELEASE SOFTWARE (fc1)
BOOTLDR: s72033_rp Software (s72033_rp-ADVENTERPRISEK9_WAN-M), Version 12.2(18)SXF, RELEASE SOFTWARE (fc1)
SLB uptime is 22 hours, 29 minutes
Time since SLB switched to active is 22 hours, 28 minutes
System returned to ROM by power cycle (SP by power on)
System restarted at 18:59:07 EST Wed Feb 1 2006
System image file is "disk0:s72033-adventerprisek9_wan-mz.122-18.SXF"
This product contains cryptographic features and is subject to United States and local country laws governing import, export, transfer and use. Delivery of Cisco cryptographic products does not imply third-party authority to import, export, distribute or use encryption. Importers, exporters, distributors and users are responsible for compliance with U.S. and local country laws. By using this product you agree to comply with applicable laws and regulations. If you are unable to comply with U.S. and local laws, return this product immediately.
ROM: System Bootstrap, Version 12.0(19990210:195103) [12.0XE 105], DEVELOPMENT SOFTWARE
BOOTLDR: 7200 Software (C7200-BOOT-M), Version 12.0(10)S, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)
IPsec-1 uptime is 23 hours, 14 minutes
System returned to ROM by reload at 17:54:32 UTC Wed Feb 1 2006
Running default software
Last reload reason: Reload Command
This product contains cryptographic features and is subject to United States and local country laws governing import, export, transfer and use. Delivery of Cisco cryptographic products does not imply third-party authority to import, export, distribute or use encryption. Importers, exporters, distributors and users are responsible for compliance with U.S. and local country laws. By using this product you agree to comply with applicable laws and regulations. If you are unable to comply with U.S. and local laws, return this product immediately.
If you require further assistance please contact us by sending email to export@cisco.com.
Cisco 7206VXR (NPE300) processor (revision D) with 122880K/40960K bytes of memory.
Processor board ID 20390414
R7000 CPU at 262 MHz, Implementation 39, Rev 1.0, 256 KB Layer 2 Cache
6 slot VXR midplane, Version 2.0
Last reset from power-on
PCI bus mb0_mb1 (Slots 0, 1, 3 and 5) has a capacity of 600 bandwidth points.
Current configuration on bus mb0_mb1 has a total of 200 bandwidth points.
This configuration is within the PCI bus capacity and is supported.
PCI bus mb2 (Slots 2, 4, 6) has a capacity of 600 bandwidth points.
Current configuration on bus mb2 has a total of 0 bandwidth points.
This configuration is within the PCI bus capacity and is supported.
Please refer to the following document "Cisco 7200 Series Port Adaptor Hardware Configuration Guidelines" on Cisco.com http://www.cisco.com for Cisco 7200 Series Router bandwidth points oversubscription and usage guidelines.
2 FastEthernet interfaces
125 KB of NVRAM
47040 KB of ATA PCMCIA card at slot 0 (sector size 512 KB)
20480 KB of flash PCMCIA card at slot 1 (sector size 128 KB)
4096 KB of flash internal SIMM (sector size 256 KB)
ROM: System Bootstrap, Version 12.2(4r)B, RELEASE SOFTWARE (fc1)
IPsec-2 uptime is 1 day, 1 hour, 13 minutes
System returned to ROM by error - an Error Interrupt, PC 0x628F59A0 at 16:39:28 UTC Wed Feb 1 2006
System image file is "disk0:c7200-jk9s-mz.124-4.T1"
This product contains cryptographic features and is subject to United States and local country laws governing import, export, transfer and use. Delivery of Cisco cryptographic products does not imply third-party authority to import, export, distribute or use encryption. Importers, exporters, distributors and users are responsible for compliance with U.S. and local country laws. By using this product you agree to comply with applicable laws and regulations. If you are unable to comply with U.S. and local laws, return this product immediately.
If you require further assistance please contact us by sending email to export@cisco.com.
Cisco 7206VXR (NPE400) processor (revision A) with 229376K/32768K bytes of memory.
Processor board ID 23655916
R7000 CPU at 350 MHz, Implementation 39, Rev 3.3, 256 KB Layer 2 Cache
6 slot VXR midplane, Version 2.1
Last reset from power-on
PCI bus mb0_mb1 (Slots 0, 1, 3 and 5) has a capacity of 600 bandwidth points.
Current configuration on bus mb0_mb1 has a total of 200 bandwidth points.
This configuration is within the PCI bus capacity and is supported.
PCI bus mb2 (Slots 2, 4, 6) has a capacity of 600 bandwidth points.
Current configuration on bus mb2 has a total of 600 bandwidth points
This configuration is within the PCI bus capacity and is supported.
Please refer to the following document "Cisco 7200 Series Port Adaptor Hardware Configuration Guidelines" on Cisco.com http://www.cisco.com for Cisco 7200 Series Router bandwidth points oversubscription and usage guidelines.
2 FastEthernet interfaces
1 Virtual Private Network (VPN) Module
125 KB of NVRAM
46976 KB of ATA PCMCIA card at slot 0 (sector size 512 KB)
4096 KB of flash internal SIMM (sector size 256 KB)
Configuration register is 0x0 (will be 0x2102 at next reload)
ROM: System Bootstrap, Version 12.2(7r) [cmong 7r], RELEASE SOFTWARE (fc1)
ROM: C2600 Software (C2600-IK9O3S3-M), Version 12.2(15)T14, RELEASE SOFTWARE (fc4)
S1 uptime is 24 weeks, 5 days, 2 hours, 3 minutes
System returned to ROM by power-on
System image file is "flash:c2600-ik9o3s3-mz.122-15.T14"
This product contains cryptographic features and is subject to United States and local country laws governing import, export, transfer and use. Delivery of Cisco cryptographic products does not imply third-party authority to import, export, distribute or use encryption. Importers, exporters, distributors and users are responsible for compliance with U.S. and local country laws. By using this product you agree to comply with applicable laws and regulations. If you are unable to comply with U.S. and local laws, return this product immediately.