SatLink VSAT User Guide
Publication no. 101557
Copyright © 2009 – STM Group, Inc.
Page 92 (160)
has to flow through the VLAN interfaces. Make sure that the Ethernet interfaces connected to the STM
SatLink VSAT also operates in VLAN trunk mode (802.1Q) and provides the correct VLAN tag values.
The DHCP server is disabled when the Ethernet interface operates in VLAN trunk mode. The hosts on
each VLAN must either get their IP addresses through manual configuration or there must be another
device on each VLAN that acts as a DHCP server.
By default, all traffic from established VLAN interfaces is mapped to the common satellite channel. By
explicit configuration, each established VLAN can be tied to a GRE tunnel. Then, the specific VLAN
traffic that matches the GRE subnet of the associated GRE tunnel will flow into this GRE tunnel; other
traffic from the VLAN will be routed to the appropriate interface, which may be the DVB interface or an
unblocked VLAN interface. Traffic that comes out of the GRE tunnel gets the associated VLAN tag at
submission to the LAN. Only packets with destination that matches the subnet of the VLAN interface will
be forwarded, traffic to other destinations is silently discarded. Thus the subnet at the remote GRE tunnel
endpoint should not exceed the subnet of the VLAN interface.
It is assumed that the tunnel destination of each GRE tunnel terminates in a device that is configured to
map to the same VLAN as the local end, as required. Note that the STM SatLink network is an IP
network and not an Ethernet MAC bridge, and thus the VLAN tag will not be carried through the SatLink
network, but must be regenerated locally at the GRE egress point, if required.
Let’s say that you want to connect VLAN 25 and VLAN 27 over the same SatLink VSAT, connecting to
two routers with addresses 10.20.1.1 and 10.20.1.2.
First, establish a local VLAN interface for each of the applicable VLANs:
# eth vlan 25
# eth vlan 27
By default, inter-VLAN communication is blocked. Alternatively, each of the VLANs can explicitly be
allowed local inter VLAN communications through the SatLink VSAT as the local VLAN interface is
established. Traffic is then allowed to flow locally between two VLANs if both are explicitly allowed
inter-VLAN communication.
How to establish the VLAN interfaces and also allow local inter VLAN communication between VLAN
25 and VLAN 27:
# eth vlan –allow 25
# eth vlan –allow 27
Then, find the automatically assigned interface IDs for the VLAN interfaces:
# eth show
VLAN Interfaces:
----------------------
If VLAN ID
11 25
12 27
Secondly, give each of the VLAN interfaces an IP address and an IP subnet. The interface IP address
must be reachable through the SatLink network so that the GRE tunnel packets from the other side of
each GRE tunnel reach the respective VLAN interface!
# ip set 11 10.10.21.1 255.255.255.0
To Next Page
Loading...
