Russian Doll Model

The RDM model is defined using the following equations:

SUM (Reserved (CTc)) ≤ BCb

where the SUM is across all values of c in the range b ≤ c ≤ (MaxCT - 1), and BCb is the bandwidth constraint of CTb.

BC0= Max-Reservable-Bandwidth, so that:

SUM (Reserved(CTc)) ≤ Max-Reservable-Bandwidth,

where the SUM is across all values of c in the range 0 ≤ c ≤ (MaxCT - 1)

An LSP of class-type CTc, setup priority p, holding priority h (h=<p), and bandwidth B is admitted into a link if the following condition is satisfied:

B ≤ Unreserved Bandwidth for TE-Class[i]

where TE-Class [i] maps to <CTc, p> in the definition of the TE classes on the node. The bandwidth reservation is effected at the holding priority, that is, in TE-class [j] = <CTc, h>. As such, the reserved bandwidth for CTc and the unreserved bandwidth for the TE classes using CTc are updated as follows:

Reserved(CTc) = Reserved(CTc) + B

Unreserved TE-Class [j] = Unreserved (CTc, h) = Min [

BCc - SUM (Reserved (CTb, q) for 0≤q ≤ h, c ≤ b ≤ 7,

BC(c-1) – SUM (Reserved (CTb, q) for 0≤q ≤ h, (c-1) ≤ b ≤ 7,

…….

BC0 - SUM (Reserved (CTb, q) for 0≤q ≤ h, 0 ≤ b ≤ 7]

Unreserved TE-Class [i] = Unreserved (CTc, p) = Min [

BCc - SUM (Reserved (CTb, q) for 0≤q ≤ p, c ≤ b ≤ 7,

BC(c-1) – SUM (Reserved (CTb, q) for 0≤q ≤ p, (c-1) ≤ b ≤ 7,

…….

BC0 - SUM (Reserved (CTb, q) for 0≤q ≤ p, 0 ≤ b ≤7]

The same is done to update the unreserved bandwidth for any other TE class making use of the same CTc. These new values are advertised to the rest of the network at the next IGP-TE flooding.