Juniper MX Series

Hierarchical CoS

This section details Hierarchical CoS. Before the deep dive, let’s get some terminology and basic concepts out of the way via Table 5-9 and its terminology definitions.

Table 5-9. H-CoS and MX Scheduling Terminology.

Term	Definition
CIR	Committed information rate, also known as “guaranteed rate.” This parameters specifies the minimum bandwidth for an IFL-Set or VLAN/IFL.
C-VLAN	A Customer VLAN, the inner tag on a dual tagged frame, often used interchangeably with IFL as each customer VLAN is associated with a unique IFL. See also S-VLAN.
Excess-priority	Keyword in a class of service scheduler container. Specifies the priority of excess bandwidth. Excess bandwidth is the bandwidth available after all guaranteed-rates have been satisfied. Options are Excess High or Low (EH/EL).
Excess-rate	Keyword in class of service traffic control profile and scheduler containers. Specifies how excess bandwidth is distributed amongst peers in a scheduler-hierarchy.
Guaranteed-rate (G-Rate)	See “CIR.” In the Trio Queuing Model, the guaranteed rate is denoted as “G” for guaranteed. G-Rate priority is Strict-High/High, Medium, or Low (SH, H, M, L). Queues transmit rate is considered a G-Rate when not overbooked, else the committed information rate in Traffic Control Profiles (TCPs).
Interface Set (IFL-Set)	A logical grouping of C-VLANs/IFLs or S-VLANs. Allows aggregate-level shaping and scheduling over a set of IFLs or S-VLANs.
Node	A scheduler node is the entity that manages dequeueing traffic from ...