Global AS Override for Auto-Derived Route Targets
Configure global AS override for EVPN auto-derived route targets by using independent AS control or unified AS control for EVPN instance types.
Global autonomous system (AS) override extends auto-derived route target functionality by allowing you to configure the AS value used in route target generation.
By default, EVPN derives route targets using the global AS value configured on the device and the SID (for example, VNI, VLAN ID, or ISID).
Benefits of Global AS Override
-
Enables independent control of import and export route target generation
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Supports per-VNI or per-bridge-domain customization
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Reduces the need for manual route target configuration
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Improves scalability in EVPN deployments with multiple VNIs
Understanding Global AS Override
You can configure global AS override using one of the following methods:
Independent AS Control
You can configure separate AS values for import and export route target generation.
-
import-as:Generates additional route targets using the specified AS value and includes the targets in the EVPN instance auto-derived import policy for routes received from EVPN peers. -
export-as:Generates export route targets using the specified AS value for routes advertised by the device. -
A route target using the global AS is always generated.
-
Only one export AS value can be configured per VNI or bridge domain.
Unified AS Control
You can configure a single AS value (as-num) for both import and
export route target generation.
-
Generates both import and export route targets using the specified AS value for routes received from EVPN peers and routes advertised by the device.
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You cannot configure as-num with import-as or export-as.
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Only one AS value can be configured per VNI or bridge domain.
How to Configure Auto-Derived Route Targets with Global AS Override
To configure global AS override for EVPN auto-derived route targets, you can use
independent AS control (import-as and export-as)
or unified AS control (as-num) statements at the [edit
switch-options vrf-target auto] or [edit routing-instances
routing-instance-name vrf-target auto] hierarchy level.
You can configure global AS override for all VNIs in an EVPN instance or for specific
VNIs by using the vni-list option. If you do not specify a VNI
list, the configuration applies to all VNIs.
- Configure Independent AS Control for a Default Switch Instance
- Configure Unified AS Control for a Default Switch Instance
- Configure Independent AS Control for a MAC-VRF Instance
- Configure Unified AS Control for a MAC-VRF Instance
Configure Independent AS Control for a Default Switch Instance
To configure separate AS values for import and export route target generation for
a default switch instance, include the import-as and
export-as statements at the [edit switch-options
vrf-target auto] hierarchy level.
set switch-options vrf-target auto import-as 207 vni-list all set switch-options vrf-target auto export-as 207 vni-list all
The following is a sample configuration.
switch-options {
vrf-target {
target:100:101;
auto {
import-as 207 {
vni-list all;
}
export-as 207 {
vni-list all;
}
}
}
}Configure Unified AS Control for a Default Switch Instance
To configure a single AS value for both import and export route target generation
for a default switch instance, include the as-num statement at
the [edit switch-options vrf-target auto] hierarchy level.
set switch-options vrf-target auto as-num 209 vni-list all
The following is a sample configuration.
switch-options {
vrf-target {
target:100:101;
auto {
as-num 209 {
vni-list all;
}
}
}
}Configure Independent AS Control for a MAC-VRF Instance
To configure separate AS values for import and export route target generation for
a MAC-VRF instance, include the import-as and
export-as statements at the [edit routing-instances
routing-instance-name vrf-target auto] hierarchy level.
set routing-instances EVPN-MVRF vrf-target auto import-as 207 vni-list all set routing-instances EVPN-MVRF vrf-target auto export-as 207 vni-list all
The following is a sample configuration.
routing-instances {
EVPN-MVRF {
instance-type mac-vrf;
service-type vlan-aware;
route-distinguisher 81.1.1.1:3;
vrf-target {
target:103:103;
auto {
import-as 207 {
vni-list all;
}
export-as 207 {
vni-list all;
}
}
}
}
}Configure Unified AS Control for a MAC-VRF Instance
To configure a single AS value for both import and export route target generation
for a MAC-VRF instance, include the as-num statement at the
[edit routing-instances routing-instance-name vrf-target
auto] hierarchy level.
set routing-instances EVPN-MVRF vrf-target auto as-num 209 vni-list all
The following is a sample configuration.
routing-instances {
EVPN-MVRF {
instance-type mac-vrf;
service-type vlan-aware;
route-distinguisher 81.1.1.1:3;
vrf-target {
target:103:103;
auto {
as-num 209 {
vni-list all;
}
}
}
}
}