Ip Bridge Settings - ZyXEL Communications MSC1024G Series User Manual

Chapter 11 Subscriber Port Setup Screens

11.14.2 IP Bridge Settings

The IP bridge function consists of the following settings.
• Domains and VLANs
• Edge routers
• Downlink interfaces
• Routing tables
• PVCs
• ARP proxy settings
Each set of settings is discussed in more detail in the following sections.
11.14.2.1 Domains and VLAN
A domain represents an ISP. Each domain is defined by (and dominates) the VLAN that are in
it and has its own routing table and ARP table. As a result, two or more VLANs in different
domains can use the same IP subnet, and one network can support multiple ISPs.
VLANs in IP bridges are exclusive. They can be in at most one domain. In addition, VLANs in
IP bridges share the same VLAN space as regular VLANs, so VLANs in IP bridges must have
different VLAN IDs than regular VLANs.
11.14.2.1.1 Configuring VLANs for Domains
To add a VLAN to a domain,
1 Add (Join) a new (undefined) VLAN ID to the domain.
2 Create the VLAN in the system using the regular screens or commands for VLANs.
To remove a VLAN from a domain,
1 Delete the VLAN from the system using the regular screens or commands for VLANs.
2 Remove (Leave) the VLAN ID from the domain.
11.14.2.2 Edge Routers
Edge routers are usually the gateways that are provided to the subscribers. They can also be
gateways that are specified in static routing table entries. Each edge router, in addition to its IP
address, has an associated VLAN ID. When the MSC forwards a frame to an edge router, it
uses this VLAN ID to replace whatever VLAN ID the subscriber specified. The MSC also
uses the VLAN ID to identify the domain the edge router is in.
If two edge routers are in different domains, it is possible for them to have the same IP
address.
11.14.2.3 Downlink Interfaces
Downlink interfaces provide forwarding information for downstream traffic. The MSC learns
some of this information by snooping DHCP packets. For static IP addresses, you should
provide this information manually. In this case, specify the VLAN ID and, optionally, the PVC
for a range of IP addresses. The MSC uses the VLAN ID to identify the domain the downlink
interface is in. Downlink interfaces in the same domain cannot have overlapping IP addresses.
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MSC1000G/1024G/1224G Series User's Guide