xStack
®
DGS-3600 Series Layer 3 Managed Gigabit Ethernet Switch
To configure BGP state settings on the Switch, complete the following fields:
Parameter
Description
BGP State Settings
BGP State
Use the drop-down menu to enable or disable the Border Gateway Protocol state. By
disabling the BGP protocol, all peers will be disconnected and dynamic routes will be deleted.
All the static configurations however will be reserved. If BGP is enabled again, the previous
configurations can be re-applied.
BGP AS Number Settings
BGP AS Number
Action
Toggle to
Add
or
Delete
the BGP AS number. When the BGP protocol starts, it must belong
to a single AS. The user must set the AS number before configuring any of the other
attributes. When the BGP process is deleted, all peer and route information from BGP will be
deleted. Route entries redistributed from BGP must also be canceled.
BGP AS Number (1-
65535)
Enter a BGP AS number between 1 and 65535.
BGP Global Settings
Synchronization
Usually, a BGP speaker does not advertise a route to an external neighbor unless that route
is local or exists in the IGP. By default, synchronization between BGP and the IGP is turned
off to allow the BGP to advertise a network route without waiting for route validation from the
IGP. This feature allows routers and access servers within an Autonomous System to have
the route before BGP makes it available to other autonomous systems.
Enforce First AS
This command is used to enforce the neighbor’s AS as the first AS in the AS list. When the
setting is
Enabled
, any updates received from an external neighbor that do not have the
neighbor’s configured Autonomous System (AS) at the beginning of the AS_PATH in the
received update, will be denied and the neighbor will be closed. Enabling this feature adds to
the security of the BGP network by not allowing traffic from unauthorized systems.
Always Compare
MED
Enable or disable the comparison of the Multi Exit Discriminator (MED) for paths from the
neighbors in different Autonomous Systems. By default this setting is
Disabled
.
Deterministics MED
Enable or disable to enforce the deterministic comparison of the Multi Exit Discriminator
(MED) for paths received from the neighbors within the same Autonomous System. By
default this setting is
Disabled
.
Bestpath Option
Choose from
AS Path Ignore
,
Compare Router ID
,
Med Confed
,
MED Missing As Worst
, and
Compare Confed Aspath
.
AS Path Ignore –
If selected, the BGP process will ignore the AS path in the path selection
process.
Compare Router ID
– If selected, the BGP process will include the router ID in the path
selection process. Similar routes are compared and the route with the lowest router ID is
selected.
Med Confed
– If selected, the BGP process will compare the MED for the routes that are
received from confederation peers. For routes that have an external AS in the path, the
comparison does not occur.
MED Missing As Worst
– If selecteded, the BGP process will assign a value of infinity to
routes that are missing the Multi Exit Discriminator (MED) attribute. If disabled, the BGP
process will assign a value of zero to routes that are missing the Multi Exit Discriminator
(MED) attribute, causing this route to be chosen as the best path.
Compare Confed Aspath
-
If selected, the BGP process will compare the confederation AS
path length of the routes received. The shorter the confederation AS path length, the better
the route is.
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