--> MPLS Stands for Multi Protocol Label Switching
--> MPLS uses LABEL for forwarding data or packets between the routers.
---> In order MPLS to work IP CEF need to be enabled on the router.
---> MPLS inserts 32 bit header between Layer 2 and Layer 3 Header , Thats why some times we will say MPLS will working in Layer 2.5.
--> This 32 bits are divided
i) 20 bits for Label Allocation ( Used for Label Creation)
ii) 8 bits TTL Value ( Decrements by one whenever packet is moving from one router to other)
iii) 1 bit for bottom of stack ( Indicates this label is inner label or outer label)
iv) 3 bits of Experimental ( QOS)
--> Basically an packet can have more than one label based upon some conditions, if it is having more than one label, it is called as label stack.
i) In case of MPLS VPN --- TWO Labels ( First Label points to egress router and Second Label indicates VPN )
ii) In case of MPLS TE -- Two or more
iii) In case of MPLS VPN with MPLS TE --- Three or more
--> MPLS uses LABEL for forwarding data or packets between the routers.
---> In order MPLS to work IP CEF need to be enabled on the router.
---> MPLS inserts 32 bit header between Layer 2 and Layer 3 Header , Thats why some times we will say MPLS will working in Layer 2.5.
--> This 32 bits are divided
i) 20 bits for Label Allocation ( Used for Label Creation)
ii) 8 bits TTL Value ( Decrements by one whenever packet is moving from one router to other)
iii) 1 bit for bottom of stack ( Indicates this label is inner label or outer label)
iv) 3 bits of Experimental ( QOS)
--> Basically an packet can have more than one label based upon some conditions, if it is having more than one label, it is called as label stack.
i) In case of MPLS VPN --- TWO Labels ( First Label points to egress router and Second Label indicates VPN )
ii) In case of MPLS TE -- Two or more
iii) In case of MPLS VPN with MPLS TE --- Three or more
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