Zte ZXR10 8900E series User Manual (English)

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ZXR10 8900E series Core Switch Product Description

ZTE Confidential Proprietary

Figure 3-5 MPLS header structure

MPLS decides forwarding by label. A label is a 20-bit identifier, only having local effect in

one hop link. What is identified by a label is a group of packets called Forwarding

Equivalence Class (FEC), which can be all packets to the same destination address

prefix or can be introduced with QoS to make the packets having the same service quality

requirements belong to the same FEC. The packets belonging to the same FEC are

forwarded according to the same forwarding policy.

When a packet without a label enters an MPLS domain, the edge LSR will analyze the

destination address carried in the header, class this packet to an FEC according to QoS

requirement, add the corresponding label of this FEC to the packet and then forward it to

the next hop. The intermediate LSR maintains a table of mapping relations between

incoming label, outgoing label and forwarding direction. When receiving a packet with a

label, it will search the mapping relation table by the incoming label carried by the packet

to obtain the outgoing label and forwarding direction, replace the incoming label with the

effective outgoing label and then send it to the next hop. When the packet leaves the

MPLS domain, the label will be deleted at the edge LSR, turn back to a packet without

label and be sent to the next hop.

In forwarding, the label can be processed in the form of stack. The label value at the top

of the label stack is the effective label, and LSR forwards packets by the top label of the

stack. When a packet enters an MPLS domain, a label is pushed in the label stack

occupying the top of the stack; at this time the stack depth increases by 1. The LSR in

this MPLS domain only checks and replaces the top label and ignores the other labels.

When the packet leaves the MPLS domain, POP operation is performed, and the label

stack turns back to the original depth before entering the MPLS domain. The packet

without label can be regarded as empty label stack; adding label to it when it first enters

MPLS network environment can also be regarded as PUSH operation. In this way, MPLS

can easily realize layered network. The depth of label stack indicates the network layer:

when the packet passes a tunnel or a lower-level MPLS network, the depth of the label

stack will increase; on the contrary, when the packet returns to the upper-level network,

the depth decreases.

At present ZXR10 8900E series provides complete MPLS protocol with the major

functions as below:

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Zte ZXR10 8900E series Specifications

General

Series	ZXR10 8900E
Category	Switch
Storage Temperature	-40°C to 70°C
Relative Humidity	5% to 95% (non-condensing)
Type	Modular switch
Port Density	Up to 576 x 10GE ports, 144 x 40GE ports
Ports	10GE, 40GE, 100GE
Redundancy	Redundant power supplies, fans, and control modules
Network Protocols	IPv4/IPv6, MPLS, VXLAN
Management	CLI, SNMP, Web
Power Supply	AC/DC
Weight	Varies by configuration
Operating Temperature	0°C to 45°C
Power Consumption	Varies by configuration
Slots	8