1-7
Cisco ASA Series CLI Configuration Guide
Chapter 1 Configuring a Cluster of ASAs
Information About ASA Clustering
•
Cluster Control Link Latency and Reliability, page 1-8
•
Cluster Control Link Failure, page 1-8
Cluster Control Link Traffic Overview
Cluster control link traffic includes both control and data traffic.
Control traffic includes:
•
Master election. (See the
“Cluster Members” section on page 1-2
.)
•
Configuration replication. (See the
“Configuration Replication” section on page 1-10
.)
•
Health monitoring. (See the
“Unit Health Monitoring” section on page 1-9
.)
Data traffic includes:
•
State replication. (See the
“Data Path Connection State Replication” section on page 1-9
.)
•
Connection ownership queries and data packet forwarding. (See the
Connections Across the Cluster” section on page 1-17
Cluster Control Link Network
Each cluster control link has an IP address on the same subnet. This subnet should be isolated from all
other traffic, and should include only the ASA cluster control link interfaces.
For a 2-member cluster, do not directly-connect the cluster control link from one ASA to the other ASA.
If you directly connect the interfaces, then when one unit fails, the cluster control link fails, and thus the
remaining healthy unit fails. If you connect the cluster control link through a switch, then the cluster
control link remains up for the healthy unit.
Sizing the Cluster Control Link
You should assign an equal amount of bandwidth to the cluster control link as you assign for through
traffic. For example, if you have the ASA 5585-X with SSP-60, which can pass 14 Gbps per unit
maximum in a cluster, then you should also assign interfaces to the cluster control link that can pass
approximately 14 Gbps. In this case, you could use 2 Ten Gigabit Ethernet interfaces in an EtherChannel
for the cluster control link, and use the rest of the interfaces as desired for data links.
Cluster control link traffic is comprised mainly of state update and forwarded packets. The amount of
traffic at any given time on the cluster control link varies. For example state updates could consume up
to 10% of the through traffic amount if through traffic consists exclusively of short-lived TCP
connections. The amount of forwarded traffic depends on the load-balancing efficacy or whether there
is a lot of traffic for centralized features. For example:
•
NAT results in poor load balancing of connections, and the need to rebalance all returning traffic to
the correct units.
•
AAA for network access is a centralized feature, so all traffic is forwarded to the master unit.
•
When membership changes, the cluster needs to rebalance a large number of connections, thus
temporarily using a large amount of cluster control link bandwidth.
A higher-bandwidth cluster control link helps the cluster to converge faster when there are membership
changes and prevents throughput bottlenecks.
Summary of Contents for 5505 - ASA Firewall Edition Bundle
Page 28: ...Glossary GL 24 Cisco ASA Series CLI Configuration Guide ...
Page 61: ...P A R T 1 Getting Started with the ASA ...
Page 62: ......
Page 219: ...P A R T 2 Configuring High Availability and Scalability ...
Page 220: ......
Page 403: ...P A R T 2 Configuring Interfaces ...
Page 404: ......
Page 499: ...P A R T 2 Configuring Basic Settings ...
Page 500: ......
Page 533: ...P A R T 2 Configuring Objects and Access Lists ...
Page 534: ......
Page 601: ...P A R T 2 Configuring IP Routing ...
Page 602: ......
Page 745: ...P A R T 2 Configuring Network Address Translation ...
Page 746: ......
Page 845: ...P A R T 2 Configuring AAA Servers and the Local Database ...
Page 846: ......
Page 981: ...P A R T 2 Configuring Access Control ...
Page 982: ......
Page 1061: ...P A R T 2 Configuring Service Policies Using the Modular Policy Framework ...
Page 1062: ......
Page 1093: ...P A R T 2 Configuring Application Inspection ...
Page 1094: ......
Page 1191: ...P A R T 2 Configuring Unified Communications ...
Page 1192: ......
Page 1333: ...P A R T 2 Configuring Connection Settings and QoS ...
Page 1334: ......
Page 1379: ...P A R T 2 Configuring Advanced Network Protection ...
Page 1380: ......
Page 1475: ...P A R T 2 Configuring Modules ...
Page 1476: ......
Page 1549: ...P A R T 2 Configuring VPN ...
Page 1550: ......
Page 1965: ...P A R T 2 Configuring Logging SNMP and Smart Call Home ...
Page 1966: ......
Page 2059: ...P A R T 2 System Administration ...
Page 2060: ......
Page 2098: ...1 8 Cisco ASA Series CLI Configuration Guide Chapter 1 Troubleshooting Viewing the Coredump ...
Page 2099: ...P A R T 2 Reference ...
Page 2100: ......