AWS Direct Connect | Local preference communities for private virtual interface Flashcards
I want to migrate my existing public virtual interface to recieve global prefixes; how can I do this migration?
Local preference communities for private virtual interface
AWS Direct Connect | Networking & Content Delivery
You have two options to do such a migration. First, create a new public virtual interface, migrate traffic from your existing public virtual interface to the newly created public virtual interface; delete your old public virtual interface. Second, open a support case to request scope change for your existing public virtual interface, you will experience a Border Gateway Protocol flap during the scope change.
What is this feature?
Local preference communities for private virtual interface
AWS Direct Connect | Networking & Content Delivery
This feature provides support for local preference communities for private virtual interfaces. With communities, customers can influence the return path for traffic sourced from VPC address space.
Can I use this feature for my existing EBGP sessions?
Local preference communities for private virtual interface
AWS Direct Connect | Networking & Content Delivery
Yes, all existing BGP sessions on private virtual interfaces support the use of local preference communities.
Do you charge additionally for this feature?
Local preference communities for private virtual interface
AWS Direct Connect | Networking & Content Delivery
There is no additional charge for using this feature.
Will this feature be available on both Public and Private Virtual Interfaces?
Local preference communities for private virtual interface
AWS Direct Connect | Networking & Content Delivery
No, this feature is currently available for private virtual interfaces only.
Will this feature work with Direct Connect Gateway?
Local preference communities for private virtual interface
AWS Direct Connect | Networking & Content Delivery
Yes, this feature will work with private virtual interfaces attached with Direct Connect Gateway.
Can I verify communities being received by AWS?
Local preference communities for private virtual interface
AWS Direct Connect | Networking & Content Delivery
No, at this time we do not provide such monitoring features.
What are the supported local preference communities for Direct Connect private virtual interface?
Local preference communities for private virtual interface
AWS Direct Connect | Networking & Content Delivery
The following communities are supported for private virtual interface and are evaluated in order of lowest to highest preference. Communities are mutually exclusive. Prefixes marked with the same communities, and bearing identical MED*, AS_PATH attributes are candidates for multi-pathing.
7224: 7100 – Low Preference
7224: 7200 – Medium Preference
7224: 7300 – High Preference
What is the default behavior in case I do not use the supported communities?
Local preference communities for private virtual interface
AWS Direct Connect | Networking & Content Delivery
If you do not specify Local Preference communities for your private VIF, the default local preference is based on the distance to the Direct Connect Locations from the local region. In such situation, egress behavior across multiple VIFs from multiple Direct Connect Locations may be arbitrary.
I have two private VIFs on a physical connections at a Direct Connect location; can I use supported communities to influence egress behavior across these two private VIFs?
Local preference communities for private virtual interface
AWS Direct Connect | Networking & Content Delivery
Yes, you can use this feature to influence egress traffic behavior between two VIFs on the same physical connection.
I have two Direct Connect connections, both 1G, I want all incoming traffic into my network load balanced across these two connections, can I use community based routing to achieve such load balancing across the locations?
Local preference communities for private virtual interface
AWS Direct Connect | Networking & Content Delivery
Yes, you can use community based routing to enable load balancing across Direct Connect locations. To do so, any prefixes requiring load-balancing must be marked with the same communities.
Will the local preference communities feature support failover?
Local preference communities for private virtual interface
AWS Direct Connect | Networking & Content Delivery
Yes. This can be accomplished by advertising prefixes over the primary/active virtual interface with a community for higher local preference than prefixes advertised over the backup/passive virtual interface. This feature is backwards compatible with pre-existing methods for achieving failover; if your Direct Connect is currently configured for failover, no additional changes are necessary.
I have already configured my routers with AS_PATH, do I need to change the configuration to use community tags and disrupt my network?
Local preference communities for private virtual interface
AWS Direct Connect | Networking & Content Delivery
No, we will continue to respect AS_PATH attribute. This feature is an additional knob you can use to get better control over the incoming traffic from AWS. Direct Connect follows the standard approach for path selection. Bear in mind that local preference is evaluated before the AS_PATH attribute.
I have two Direct Connect connections, one is 1G and another is 10G, and both are advertising the same prefix. I would like to receive all traffic for this destination across the 10G Direct Connect connection, but still be capable of failing over to the 1G connection. Can local preference communities be used to balance traffic in this scenario?
Local preference communities for private virtual interface
AWS Direct Connect | Networking & Content Delivery
Yes. By marking the prefix advertised over the 10G Direct Connection with a community of a higher local preference, it will be the preferred path. In the event that the 10G fails or the prefix withdrawn, the 1G interface will become the return path.
