| copyright | lastupdated | keywords | subcollection | ||
|---|---|---|---|---|---|
|
2019-04-02 |
diversity, redundancy, schematics, deployment, configuration, global routing, ECMP, Dual XCRs, model |
direct-link |
{:shortdesc: .shortdesc} {:new_window: target="_blank"} {:codeblock: .codeblock} {:pre: .pre} {:screen: .screen} {:tip: .tip} {:download: .download}
{: #models-for-diversity-and-redundancy-in-direct-link}
This document gives a series of schematics related to issues of redundancy and diversity, which can help you find a model for creating the most successful {{site.data.keyword.cloud}} Direct Link deployment to meet your needs. The schematics are arranged in increasing levels of complexity and also according to the Direct Link offering that each one is illustrating. Direct Link is not an inherently redundant service at the cross-connect router (XCR), customers have the responsibility for creating redundancy through their border gateway protocol (BGP) schemas.
{: #section-1-diversity-models}
The configurations shown in this group rely on the fact that all of the assets are located in the same PoP and in the same global market.
Figure 1: Direct Link Exchange with diversity, in the same PoP (non-AZ)
Figure 2: Direct Link Connect with diversity in the same PoP (non-AZ)
Figure 3: Direct Link Dedicated with diversity in same PoP (non-AZ)
{: #section-2-diversity-models}
The configurations shown in this group offer options for connecting across local availability zones and markets.
{: #section-2-part-a}
Figure 4: Direct Link Exchange with diversity in a local AZ (WDC, DAL, FRA, LON)
Figure 5: Direct Link Connect with diversity in a local AZ (WDC, DAL, FRA, LON)
Figure 6: Direct Link Dedicated with diversity in a local AZ (WDC, DAL, FRA, LON)
{: #section-2-part-b}
Figure 7: Direct Link Connect with diversity and Global Routing
Figure 8: Direct Link Exchange with diversity and Global Routing
Figure 9: Direct Link Dedicated with diversity and Global Routing
{: #more-about-ecmp}
ECMP is a feature of BGP. Some customers have asked us about using ECMP as a way to achieve redundancy. However, ECMP alone is not sufficient. This section explains why.
Q: Is ECMP the way to go for redundant connections? What alternatives exist?
ECMP isn’t designed for creating redundant connections but for balancing the load over two links. With ECMP on {{site.data.keyword.cloud_notm}}, both connections must terminate to the same IBM Cloud cross-connect router (XCR), which makes it a single point of failure. (In other words, ECMP can only be provisioned as two sessions on the same {{site.data.keyword.cloud_notm}} XCR.)
Figure 10: ECMP provisioning
{: #how-to-achieve-diversity-and-redundancy}
If you are looking for High Availability (HA) or full redundancy: set up two links into different XCRs in the same data center (for example DAL03). Then failover as needed using BGP configurations.
Figure 11: ECMP with Dual XCRs
