Managing bandwidth across multiple inter-region connections is error-prone when traffic volumes fluctuate — each connection requires separate allocation and manual adjustment. Bandwidth multiplexing lets Cloud Connect Network (CCN) transit routers share the bandwidth of an existing inter-region connection with regional transit routers in the same area, so you manage one connection instead of two.
Bandwidth multiplexing is disabled by default. to enable it.
Key concepts
Regional transit router
A transit router deployed in a standard region, not in a CCN area. Examples: the transit router in the China (Hangzhou) region or the Singapore region.
CCN transit router
A transit router deployed in a CCN area. Examples: the CCN transit router in the Chinese mainland area or the Singapore area of CCN.
Intra-area and inter-area
These terms describe the relationship between a transit router and the CCN transit router connected to the same Cloud Enterprise Network (CEN) instance:
Intra-area: both transit routers are in the same CCN area.
Inter-area: the transit routers are in different CCN areas.
CCN is deployed by area. Each area contains one or more regions. For details about areas and regions, see CCN areas and CEN regions.
How it works
Without bandwidth multiplexing, inter-region traffic between TR1 (CCN transit router) and TR3, and between TR2 (regional transit router) and TR3, travels over separate inter-region connections. Because traffic volumes fluctuate, predicting and adjusting bandwidth for each connection individually is difficult and can lead to congestion.
With bandwidth multiplexing enabled, traffic from TR1 to TR3 is rerouted through Inter-region Connection 1 (between TR2 and TR3). Inter-region Connection 2 requires no separate bandwidth allocation.
Within the same CCN area, a CCN transit router communicates with regional transit routers in that area by default — no bandwidth allocation is required. Bandwidth allocation is only required for communication between transit routers in different CCN areas.
Chinese mainland area CCN transit router to China (Hangzhou) regional transit router: communicates by default, no bandwidth allocation needed.
Chinese mainland area CCN transit router to UK (London) regional transit router: bandwidth allocation required. Intra-area bandwidth is determined by the bandwidth of the Smart Access Gateway (SAG) instance connected to the CCN instance.
Use cases
Single CCN transit router
A CCN transit router shares the bandwidth of one inter-region connection with a regional transit router in the same area. See the How it works section for details.
Multiple CCN transit routers
Bandwidth multiplexing also applies when multiple CCN transit routers are involved. The following figure shows an example with the Chinese mainland and Singapore areas of CCN.
Limitations
| Condition | Behavior | Reason |
|---|---|---|
| Feature availability | Disabled by default. to enable it. | — |
| Supported connections | Only inter-region connections attached to CCN transit routers support bandwidth multiplexing. | — |
| Regional transit router is Enterprise Edition | Create an inter-region connection between the CCN transit router and the regional transit router. No bandwidth allocation is needed for this connection. | Without this connection, traffic from the CCN transit router cannot be rerouted over the shared inter-region connection. |
| Regional transit router is Basic Edition | No inter-region connection is required. The CCN transit router and regional transit router communicate by default. | — |
Configure bandwidth multiplexing
This example uses the following topology:
An enterprise has a VPC in China (Hangzhou), a VPC in UK (London), and a data center in the Chinese mainland. Inter-region Connection 1 runs between the China (Hangzhou) transit router and the UK (London) transit router. Inter-region Connection 2 runs between the CCN transit router (Chinese mainland area) and the UK (London) transit router.
Because traffic between VPC1 and VPC2 fluctuates heavily, adjusting bandwidth for two separate connections is time-consuming. Enabling bandwidth multiplexing routes the data center's traffic over Inter-region Connection 1 — requiring only one connection to manage.
Prerequisites
Before you begin, ensure that you have:
An inter-region connection between the transit routers. See Manage inter-region connections. In this example, Inter-region Connection 1 is created between the transit routers in the China (Hangzhou) and UK (London) regions, and Inter-region Connection 2 is created between the CCN transit router in the Chinese mainland area and the transit router in the UK (London) region.
If the China (Hangzhou) transit router is Enterprise Edition: an inter-region connection between the CCN transit router (Chinese mainland area) and that regional transit router. Without this connection, traffic from the CCN transit router cannot be rerouted over Inter-region Connection 1.
If the China (Hangzhou) transit router is Basic Edition: no additional inter-region connection required.
Steps
Log on to the CEN console.
On the Instances page, click the ID of the CEN instance.
On the Basic Information > Transit Router tab, click the ID of the transit router for which you want to enable bandwidth multiplexing.
Click the Cross-region Connections tab.
Find the inter-region connection and click Configure Bandwidth Multiplexing in the Actions column.
In the Configure Bandwidth Multiplexing dialog box, select a connection from the Source Connection drop-down list, then click OK.
Result
After the configuration is applied, the bandwidth between the CCN transit router (Chinese mainland area) and the UK (London) transit router drops to 0 Mbit/s. Traffic from the CCN transit router is rerouted through the China (Hangzhou) region.
To verify the configuration, go to the Cross-region Connections tab, find the inter-region connection, and click View Detour Path in the Connection Region column.
What to do next
Adjust inter-region connection bandwidth
After enabling bandwidth multiplexing, adjust the bandwidth of inter-region connections whose bandwidth is multiplexed. In the example above, the bandwidth of Inter-region Connection 1 needs to be adjusted to ensure data transmission.
See Modify the maximum bandwidth value of inter-region connections.
Disable bandwidth multiplexing
On the Cross-region Connections tab of the CCN transit router, click Disable Bandwidth Multiplexing in the Actions column.
In the Disable Bandwidth Multiplexing dialog box, select a bandwidth option and click OK:
Option Resulting bandwidth Downgrade to 10 Kbit/s Sets the inter-region connection bandwidth to 10 Kbit/s. Set to Minimum Bandwidth of Current Connection Sets the bandwidth to the minimum value recorded during the bandwidth multiplexing period.
Example
The following figure shows the bandwidth values for each connection when bandwidth multiplexing is enabled for Connection A.
After disabling bandwidth multiplexing:
Downgrade to 10 Kbit/s: TR A to TR C = 10 Kbit/s, TR A to TR D = 10 Kbit/s, TR B to TR C = 10 Kbit/s, TR B to TR D = 10 Kbit/s.
Set to Minimum Bandwidth of Current Connection: TR A to TR C = 2 Mbit/s, TR A to TR D = 2 Mbit/s, TR B to TR C = 5 Mbit/s, TR B to TR D = 3 Mbit/s.