Multiple routing tables in Netscaler ADC
IP routing in Citrix Netscaler ADC
Citrix ADC embeds 3 different routing tables :
- NS Kernel routing table : Used by Citrix ADC in packet forwarding. Holds subnet routes corresponding to the NSIP and to each SNIP and MIP. Holds any static routes added through the CLI. This routing table is configured through the GUI or CLI interface.
- Network service module : Contains the advertisable routes distributed by the dynamic routing protocols to their peers in the network. This routing table is configured using the vtysh mode (ZebOS).
- FreeBSD routing table : Facilitate initiation and termination of management traffic (telnet, ssh, etc.).
Netscaler ADC routing suite based on ZebOS® IP Infusion Layer 2, Layer 3, MPLS network stack. ZebOS® can be accessed using vtysh netscaler CLI command. IPv4 & IPv6 supported dynamic routing protocols are :
- Routing Information Protocol (RIP) : version 2 & RIPng for IPv6
- Open Shortest Path First (OSPF) : version 2 & version 3 for IPv6
- Border Gateway Protocol (BGP)
- ISIS Protocol
Routing tables synchronization
NS kernel routing table (GUI & CLI configuration) and Network service module (ZebOS) are ynchronized using the following vtysh commands :
- Use ns-route-install commands to push routes from ZebOS to NS Kernel routing table
- Use redistribute kernel command in ZebOS dynamic routing protocols configuration to advertise routes configured in NS Kernel routing table.