IGMP
Q: Which managed switches support IGMP?
A: All Sixnet Managed switches fully support IGMP.
Q: What versions of IGMP do Sixnet switches support?
A: The ET, SL, SLX, EK and EF series all support IGMP V1 and V2. The EL Series supports IGMP V1, V2 and V3.
Q: Do Sixnet switches support IGMP Snooping?
A: Yes, all Sixnet switches support both active and passive IGMP Snooping. Active snooping actively controls the flow of multicast data; passive snooping only listens to the IGMP messages on the network.
Q: What are the differences between the multicast suppression modes in the ET, SL(X), EK/EF series?
A: The multicast suppression modes suppress packets as follows:
- None–Multicast packets are sent to all ports unless IGMP is enabled and one or more clients have sent IGMP Report requests.
- IP Multicast Groups–Multicast packets corresponding to IP multicast groups (with MAC addresses starting 01:00:5e) are suppressed unless one or more clients have sent IGMP Report messages. Multicast packets with other addresses (any other packet with a MAC address starting 01) are sent to all ports.
- All Unreserved Multicast–Multicast packets with reserved multicast addresses (01:80:c2:00:00:0x where x is 0..f) are sent to all ports. All other multicast packets are suppressed unless one or more clients have sent IGMP Report messages.
Message Rate Limiting Series
Q: Which managed switches support Message Rate Limiting?
A: All Sixnet switches support Message Rate Limiting.
Q: What exactly does Message Rate Limiting do?
A: Message rate limiting restricts the amount of Broadcast and Multicast traffic that passes through the switch. It has no effect on other types of communication, such as unicast.
Q: Is message rate limiting adjustable?
A: On all ET, SL, SLX, EK and EF switches, rate limiting is not adjustable; it can only be enabled and disabled on a per-port basis. The rate limits are fixed based on message type and priority. The rates are as follows:
| Background | 10% of link capacity |
| Normal | 20% of link capacity |
| Expedited | 40% of link capacity |
| Urgent | 80% of link capacity |
The EL series supports fully adjustable rate limiting on both ingress and egress. This can be done on a per-port basis.
RSTP Configuration
Q: Which managed switches support RSTP?
A: All Sixnet managed switches fully support RSTP. By default, all EL series switches will have RSTP enabled. All SLX series switches with firmware 5.0 or newer will also have RSTP enabled by default.
Q: How many switches can I connect in an RSTP network?
A: You can have a maximum of 40 hops in an RSTP network. Hops are the number of connections between the two farthest points on the network. In most practical networks, this means you cannot have more that 40 switches between any two points.
Q: Can RTR and RSTP be enabled on the same switch?
A: Yes, however, a particular port may only be used for one protocol or the other. For example, if a port is part of a Real-Time-Ring, that port cannot also participate in a spanning tree.
RTR Configuration
Q: What is Real-Time-Ring?
A: Real-Time-Ring is a Sixnet proprietary protocol that provides extremely fast failure recovery in the event of a network break. It is many times faster than RSTP. However, it can only be configured in a ring, whereas RSTP can be arranged in almost any configuration.
Q: How quickly does the Real-Time-Ring protocol recover from a failure?
A: RTR can typically recover in 30 ms (milliseconds) plus 5ms per hop. For example, a four-switch ring would normally recover from a failure in 50 ms.
Q: How many switches can I connect in a Real-Time Ring?
A: While there is no maximum, the larger the ring gets, the longer the network will take to recover from a failure. Our ring switches have been field tested with over 80 switches in a single ring.
Q: Which managed switches support Real-Time-Ring?
A: All Sixnet SL, SLX and EK/EF model switches support Real-Time-Ring on firmware versions 4.4.1000 and later. The EL series supports Real-Time-Ring on all firmware versions. Legacy managed switches (ET series) do not support Real-Time-Ring.
Q: Can I use RTR with another brand of ring switch, or another ring protocol?
A: No, RTR may only be used to connect to other Sixnet RTR-capable devices.
Q: How many rings can I configure using RTR?
A: You can configure up to four independent rings, as long as your device has enough ports to do so. For example, a five-port managed switch such as the SLX-5MS-1 switch can only support two rings, because it does not have enough ports to support four rings. However, the 10-port SLX-10MG-1 switch does support the full four-ring limit.
Q: Can RTR and RSTP be enabled on the same switch?
A: Yes, however, a particular port may only be used for one protocol or the other. For example, if a port is part of a Real-Time-Ring, that port cannot also participate in a spanning tree.