Flexible IP

SmartMedia version 2.8 introduced a new feature called Flexible IP. Compared with 2.7 branch it allows almost unlimited flexibility in configuration of IP interfaces on SN10k TelcoBoards. In order to fully understand the capabilities this enhancement offer we need to get through some definitions:

• Physical Ports - those are the physical Ethernet interfaces available on the TelcoBoard, fe. SN10200 has 4 of them: ETH0, ETH1, VOIP0 and VOIP1. SN10100 on the other hand only two: VOIP0 and VOIP1
• Virtual Port - an virtual entity binding together a Physical Port (or multiple Physical Ports in case bonding is required) and a VLAN Tag (or an Untagged interface)
• IP Interface - instance grouping a Virtual Port, IP configuration and a Service Role
• Service Role - group of services that can be bound to a particular IP interface: Management (WebPortal, SSH, SNMP), H.248/RADIUS, SIP/SIP-I, SIGTRAN, RTP
• Bonding - multiple Physical Ports grouped under one Virtual Port, from which group only one interface is active at time. Mostly deployed for network failover scenarios.

Layer2 

On the Virtual Port level 802.1Q VLAN tags are supported, as well as untagged traffic. Based on the VLAN ID (or untagged traffic) you can create multiple Virtual Ports. You can bind same Physical Ports to different Virtual Ports as long as the VLAN Tags don't conflict. Fe. you can have VPort1 with VLAN ID 100 created on interface VOIP0, and VPport2 with VLAN ID 200 created on the same port.

In case you would place multiple Physical Ports under one Vrtual Port a Bonding will be created. First Physical Port defined in the Virtual Port list will be used as active in this Bonding Group. Bonding is managed as a separate function and allows user to decide how the network failure will be detected:

• by default the bonding group queries Physical Port driver events and check for a Link Down error
• querying an remote IP address
• analyzing ARP replies from a defined remote host

Current limitations are:

• on SN10200 ETH0 and ETH1 untagged  Virtual Ports are reserved for system operations
• on SN10100 VLAN3 on VOIP0 and VOIP1 is reserved for system operations
• 16 Virtual Ports are supported per TelcoBoard

Layer3

Release 2.7 allowed us only to place a single IP address per Physical Port and required a TelcoBoard restart each time a reconfiguration was performed. Now in 2.8 this is a very different story. Using the IP Interface you can bind together a Virtual Port with actual Layer3 configuration (IP address, netmask, default GW).

Each IP Interface is a separate routing entity, which means no traffic is forwarded between different IP Interfaces (there is an axception in case you will configure two IP Interfaces in the sames IP subnet and place both under one Virtual Port - then they are treated as aliases). Number of IP Interfaces is limited to 16 per TelcoBoard.

As you may noticed already, there is a possibility to bind multiple IP Interfaces to one Virtual Port. Those IP Interfaces can be also located in the same IP subnet. Current limitations in this process are:

• there can be only one IP Interface dedicated to SIP, RTP or SIGTRAN role configured on a particular Virtual Port, fe. VirtualPort1 is bound to IPInterface1 carrying SIP and RTP roles; if we would decide to connect VirtualPort1 also with IPInterface2 configured for SIGTRAN (or SIP) role, the configuratio would fail
• there can be more then one IP Interfaces acting as MANAGEMENT or  H.248 bound to a particular Virtual Port, fe. fe. VirtualPort1 is bound to IPInterface1 running MANAGEMENT role; if we would decide to connect VirtualPort1 also with IPInterface2 configured for MANAGEMENT role as well, the configuratio would succeed

Last step during configuration is selecting what roles should be running on a particular IP Interface. We can choose from:

• SIP/SIP-I - SIP/SIP-i signaling stack
• RTP - allocation of media channels for each RTP stream
• SIGTRAN - SIGTRAN signaling stack
• MANAGEMENT - WebPortal, SSH, SNMP interfaces located in the Control Host
• H.248/RADIUS - H.248 MEGACO stack and RADIUS Client

There are also some limitations in the process of binding Service Roles to IP Interfaces:

• a single IP Interface can be acting as: (SIP and/or RTP and/or SIGTRAN) or MANAGEMENT or H.248/RADIUS role
• some examples of valid assignments per one IP Interface:
  • SIP+SIGTRAN+RTP
  • RTP
  • MANAGEMENT
  • H.248/RADIUS
• some examples of invalid assignments per ine IP Interface:
  • RTP + MANAGEMENT
  • MANAGEMENT + H.248/RADIUS
  • SIP + SIGTRAN + H.248/RADIUS