Load Balancing Features Supported By The Spu - Huawei quidway s7700 Configuration Manual

Quidway S7700 Smart Routing Switch
Configuration Guide - SPU
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6.2 Load Balancing Features Supported by the SPU

The load balancing features supported by the SPU and the implementation principle are as
follows.
Egress Link Load Balancing
To prevent the network availability degradation caused by the fault on the ISP's egress device
and address the problem of network access failure due to insufficient bandwidth, an enterprise
leases two or multiple Internet Service Provider (ISP) egresses. The enterprise encounters the
problem about properly using multiple ISP egresses. That is, the resources should be efficiently
used by the enterprise. Traditional policy-based routing (PBR) can relieve the impact of the
problem, but PBR is difficult to configure. In addition, the PBR is inflexible, which cannot
dynamically adapt to the network structure change. The PBR cannot distribute packets according
to the bandwidth. As a result, the link with the high throughput cannot be fully used.
Issue 01 (2011-07-15)
– Requests whose source and destination IP addresses are located in the same network
segment
The hash algorithm is applied to the scenario where requests from a user are distributed
to the same server or link, and is also applied to server load balancing. It is applied to
the scenario where all requests from a user are distributed to a server or a link. It is also
applied to firewall load balancing.
– Hash algorithm based on the HTTP URL
In the hash algorithm based on the HTTP URL, the SPU hashes the URL carried in
HTTP request packets and makes load balancing decisions according to the hash value.
After a load balancing member is selected, the SPU determines whether the member
can be used according to the bandwidth limit, connection quantity limit, and connection
rate limit. If the load balancing member cannot be used, the SPU selects the next load
balancing member according to the hash value.
Health detection
Health detection indicates that the load balancing device periodically detects the service
status of real servers or links to collect corresponding information and isolate abnormal
servers or links. The SPU can detect whether servers or links run normally.
Session stickiness
Session stickiness indicates that connection requests of a user in a period are sent to the
same server for processing.
Firewall load balancing
Based on load balancing of network devices, the firewall load balancing technology ensures
the bidirectional traffic of a session passes through the same firewall.
Firewall load balancing has the following characteristics:
– Reducing or even removing the bottleneck of the firewall (enhancing the performance
and extensibility of the network)
– Enhancing firewall availability and network security
Firewall load balancing is classified into the following types:
– Standard firewall load balancing
– Transparent firewall load balancing
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