Revision as of 18:14, 25 March 2013

Overview

When a network is created, a broadcast domain is available to plug ports. It should be interesting to proposed an option on the network creation that enable the isolation between ports in a same broadcast domain (network), similar to a common use of private VLANs with isolated port technologies (RFC 5517). This prevents communication between VMs on the same logical switch.

This functionality could be addressed case where we create a shared network between tenants, for example. This should work also with a provider network.

Possible implementation

Local proxy ARP

• ARP broadcast modifies to unicast MAC address of a local proxy ARP (gateway)
• Multicast bootp traffic modifies to unicast MAC address of the DHCP agent
• drop all other broadcast and multicast traffic
• Drop all other traffic aren't having the MAC address of the local proxy ARP as destination (broadcast, multicast, illegitimate unicast)

When a network is created, a boolean can specify if it's isolated. And when a gateway is added to the network, the gateway port enables a locale proxy ARP.

Note: If the gateway and local proxy ARP port aren't manage by Quantum (on a provider network for example), it could be possible to define trough the API (on subnet creation for example) the MAC address of the gateway/local proxy ARP.

Note: It's not sure that the local proxy ARP must be handle by the gateway. If not, we can imagine implement the local proxy ARP by a new agent with a dedicated IP.