Understanding Aggregated SONET/SDH Interfaces
Junos OS enables link aggregation of SONET/SDH interfaces; this is similar to Ethernet link aggregation, but is not defined in a public standard. Junos OS balances traffic across the member links within an aggregated SONET/SDH bundle based on the Layer 3 information carried in the packet. This implementation uses the same load balancing algorithm used for per-packet load balancing. For information about per-packet load balancing, see the Junos OS Routing Protocols Library.
You configure an aggregated SONET/SDH virtual link by specifying the link number as a physical device and then associating a set of physical interfaces that have the same speed.
Channelized OC IQ, IQE, and SONET/SDH OC48/STM16 IQE PICs do not support SONET aggregation.
SONET/SDH aggregation is proprietary to the Junos OS and might not work with other software.
Understanding Aggregated SONET/SDH Properties
Creating Aggregated SONET/SDH Interfaces
By default, no aggregated SONET/SDH interfaces are created. You must define the number of aggregated SONET/SDH interfaces by including the device-count statement at the [edit chassis aggregated-devices sonet] hierarchy level. For information about configuring device count, see Configuring Aggregated SONET/SDH Interfaces.
Starting with Junos OS Release 13.2, a maximum of 64 aggregated interfaces are supported for link aggregation of SONET/SDH interfaces. Prior to Junos OS Release 13.2, a maximum of 16 aggregated interfaces were supported for link aggregation of SONET/SDH interfaces. The aggregated SONET/SDH interfaces are numbered from as0 through as63. For more information, see the Junos OS Services Interfaces Library for Routing Devices.
Additionally, you must assign a number for the variable x for the aggregated SONET/SDH interface asx at the [edit interfaces] hierarchy level and also specify the constituent physical interfaces by including the aggregate statement at the [edit interfaces interface-name sonet-options] hierarchy level.
You can optionally specify other physical properties that apply specifically to the aggregated SONET/SDH interfaces; for details, see SONET/SDH Interfaces Overview
SONET/SDH Link Aggregation Overview
On SONET/SDH interfaces, you can associate a physical interface with an aggregated SONET/SDH interface. To associate the interface with an aggregated SONET/SDH link, include the aggregate statement at the [edit interfaces interface-name sonet-options] hierarchy level.
x is the interface instance number and can be from 0 through 63, for a total of 64 aggregated interfaces. You should not mix SONET and SDH mode on the same aggregated interface. In addition, you must also include a statement configuring asx at the [edit interfaces] hierarchy level.
Aggregated SONET/SDH Link Speed Overview
On aggregated SONET/SDH interfaces, you can set the required link speed for all interfaces included in the bundle, or specify that the bundle contains interfaces with mixed interface speeds.
For nonconcatenated interfaces on aggregated SONET/SDH interfaces, you can configure the link speed of the aggregate to match the speed of the nonconcatenated interface. For example, an OC12 PIC can have nonconcatenated interfaces with a link speed of OC3.
To set the required link speed or specify mixed interface speeds, include the link-speed statement at the [edit interfaces interface-name aggregated-sonet-options] hierarchy level.
The link speed can be one of the following values:
oc3—Links are OC3c or STM1c.
oc12—Links are OC12c or STM4c.
oc48—Links are OC48c or STM16c.
oc192—Links are OC192c or STM64c.
oc768—Links are OC768c or STM256c.
Configuring Aggregated SONET/SDH Minimum Links
On aggregated SONET/SDH interfaces, you can configure the minimum number of links that must be up for the bundle as a whole to be labeled up. By default, only one link must be up for the bundle to be labeled up.
On a T Series, TX Matrix router with SONET interfaces, the valid range for minimum-links number is from 1 through 16. When the maximum value (16) is specified, all configured links of a bundle must be up for the bundle to be labeled up.
On all other router routers, the range of valid values for minimum-links number is 1 through 8 and the maximum number of links supported in an aggregate is eight. When the maximum value (8) is specified, all configured links of a bundle must be up for the bundle to be labeled up.