GMPLS update - 60: optimizing standard label stack entries

Optimized #standard #label #stack #entries in GMPLS module. This #removes the #attributes like #label and #pointer to label. The hard-linked #custom #label #stack entries provides the label information of the stack which satisfies the same requirement. The custom out-segment entry is capable of maintaining the label of any media type, hence this will be more useful than the standard entries - which is quite limited. This will reduce the memory requirement associated with the label stack entries.

#GMPLS update 60 ...
[commit e744cbbee2f0ae3b3d88d1bba4034da0629278ff] (https://github.com/nes-repo/NES-Open-Switch/commit/e744cbbee2f0ae3b3d88d1bba4034da0629278ff)