Figure 32 Service VLAN Configuration
Enable or disable RSTP per port, using the add rapid_spanning_tree
command, see section 13.8.4 on page 110. Most of the RSTP properties are
configured using this command. However, some properties are configured
using the set rapid_spanning_tree command, see section 13.8.17 on
page 132.
Note: The same rapid spanning tree instance must be used on both ports of
the same node.
9.2 ARP and DHCP tag
The ‘arp_and_dhcp_tag’ attribute is used to define a parallel VLAN ID for the
uplink traffic to or from a switching domain. This facility is introduced because
certain aggregation switches or routers above the EFN do not switch incoming
packets back to the same port and switching domain from which they were
received. This might occur during forced forwarding if two End-users
communicate. Note that the Layer 2 switching within the router is the problem.
By creating an alternative VLAN to the same port, aggregation switches can
use a different VLAN, and thus the port will not be perceived as the same port.
Upstream traffic on the uplink is tagged according to the ordinary configured
VLAN ID for the switching domain. Downstream traffic from an uplink, which is
marked with the arp_and_dhcp_tag VLAN tag, is also accepted by this
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