Help Center/ Elastic Load Balance/ Service Overview/ Specifications of Dedicated Load Balancers
Updated on 2024-01-16 GMT+08:00
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Specifications of Dedicated Load Balancers

When you create a dedicated load balancer, you can select elastic or fixed specifications based on your service requirements. Table 1 lists the differences between the two specifications.

Table 1 Specifications comparison

Item

Elastic

Fixed

Application scenarios
  • For fluctuating traffic
  • When you need to use resources temporarily and for urgent purposes
  • For stable traffic
  • When you need to use resources for a long term

Network (TCP/UDP/TLS) load balancer performance

The performance multiplies as the number of AZs increases. Table 2 shows the maximum performance in an AZ.

The performance multiplies as the number of AZs increases. Table 4 shows the maximum performance in an AZ.

Application (HTTP/HTTPS) load balancer performance

The performance multiplies as the number of AZs increases. Table 2 shows the maximum performance in an AZ.

The performance multiplies as the number of AZs increases. Table 5 shows the maximum performance in an AZ.

Billing mode

Pay-per-use
  • Pay-per-use
  • Yearly/Monthly

Billing items
  • LCU
  • Load balancer

LCU

Capabilities

Same

Elastic Specifications

If your service traffic fluctuates greatly, you can choose elastic specifications and select network or application load balancing that best meets your service needs.

The listener protocol must match the load balancing type. For example, if you create an application load balancer, you can only add an HTTP or HTTPS listener to this load balancer.

Load balancers are available in different elastic specifications. Choose the specifications that best meet your needs. When your traffic exceeds what defined in your selected specifications, new requests will be discarded. Each specification has the following dimensions.

  • Maximum concurrent connections

    Indicates the maximum number of concurrent connections that a load balancer can handle per minute. If the number reaches the maximum connections that is defined in specifications, new requests will be discarded to ensure the performance of established connections.

  • Connections per second (CPS)

    Indicates the number of new connections that a load balancer can establish per second. If the number reaches the CPS that is defined in specifications, new requests will be discarded to ensure the performance of established connections.

  • Queries per second (QPS)

    Indicates the number of HTTP or HTTPS requests sent to a backend server per second. If the QPS reaches that is defined in specifications, new requests will be discarded to ensure the performance of established connections.

  • Bandwidth (Mbit/s)

    Indicates the maximum amount of data that can be transmitted over a connection per second.

Table 2 Maximum elastic specifications

Protocol

Maximum Concurrent Connections

CPS

QPS

Bandwidth (Mbit/s)

Network load balancing (TCP/UDP)

20,000,000

400,000

-

10,000

Network load balancing (TLS)

20,000,000

400,000

-

10,000

Application load balancing (HTTP)

8,000,000

80,000

160,000

10,000

Application load balancing (HTTPS)

8,000,000

80,000

160,000

10,000

Available elastic specifications are displayed on the console and may vary depending on regions.

Fixed Specifications

Load balancers are available in different fixed specifications. Choose the specifications that best meet your needs. When your traffic exceeds what defined in your selected specifications, new requests will be discarded. Each specification has the following dimensions

  • Maximum concurrent connections

    Indicates the maximum number of concurrent connections that a load balancer can handle per minute. If the number reaches the maximum connections that is defined in Table 4 and Table 5, new requests will be discarded to ensure the performance of existing connections.

  • Connections per second (CPS)

    Indicates the number of new connections that a load balancer can establish per second. If the number reaches the CPS that is defined in Table 4 and Table 5, new requests will be discarded to ensure the performance of established connections.

    HTTPS listeners need to create SSL handshakes to establish connections with clients, and such SSL handshakes occupy more system resources than HTTP listeners. For example, a small I application load balancer can establish 2,000 new HTTP connections per second but only 200 new HTTPS connections per second.

    For a small I application load balancer:

    • If you only add an HTTP listener, the load balancer can establish up to 2,000 new HTTP connections.
    • If you only add an HTTPS listener, the load balancer can establish up to 200 new HTTPS connections.
    • If you add an HTTPS listener and an HTTP listener, the new connections are calculated using the following formula:

      New connections = New HTTP connections + New HTTPS connections x Ratio of HTTP connections to HTTPS connections

      For a small I application load balancer, the ratio of HTTP connections to HTTPS connections is 10. For details, see Table 3.

      Table 3 New connections that a small I application load balancer can establish

      Parameter

      Scenario 1

      Scenario 2

      New HTTP connections

      1,000

      1,000

      New HTTPS connections

      50

      150

      New HTTP and HTTPS connections

      1,000 + 50 x 10 = 1,500

      1,000 + 150 x 10 = 2,500

      Description
      • The new connections do not reach the CPS (HTTP) defined in Table 5, and new requests will be properly routed.
      • The new connections reach the CPS (HTTP) defined in Table 5, and new requests will be properly routed.

      Details in the Table 3 are for reference only.

  • Queries per second (QPS)

    Indicates the number of HTTP or HTTPS requests sent to a backend server per second. If the QPS reaches that is defined in Table 5, new requests will be discarded to ensure the performance of established connections.

  • Bandwidth (Mbit/s)

    Indicates the maximum amount of data that can be transmitted over a connection per second.

Table 4 and Table 5 list the fixed specifications of dedicated load balancers.

  • Available fixed specifications are displayed on the console and may vary depending on the resources in different regions.
  • The listener protocol must match the load balancing type. For example, if you create an application load balancer, you can only add an HTTP or HTTPS listener to this load balancer.
Table 4 Fixed specifications for a network load balancer

Type

Maximum Concurrent Connections

CPS

Bandwidth (Mbit/s)

LCUs in an AZ

Small I

500,000

10,000

50

10

Small II

1,000,000

20,000

100

20

Medium I

2,000,000

40,000

200

40

Medium II

4,000,000

80,000

400

80

Large I

10,000,000

200,000

1,000

200

Large II

20,000,000

400,000

2,000

400
Table 5 Fixed specifications for an application load balancer

Type

Maximum Concurrent Connections

CPS (HTTP)

CPS (HTTPS)

QPS (HTTP)

QPS (HTTPS)

Bandwidth (Mbit/s)

LCUs in an AZ

Small I

200,000

2,000

200

4,000

2,000

50

10

Small II

400,000

4,000

400

8,000

4,000

100

20

Medium I

800,000

8,000

800

16,000

8,000

200

40

Medium II

2,000,000

20,000

2,000

40,000

20,000

400

100

Large I

4,000,000

40,000

4,000

80,000

40,000

1,000

200

Large II

8,000,000

80,000

8,000

160,000

80,000

2,000

400
  • If you add multiple listeners to a load balancer, the sum of QPS values of all listeners cannot exceed the QPS defined in each specification.
  • The bandwidth is the upper limit of the inbound or the outbound traffic. For example, for small I load balancers, the inbound or outbound traffic cannot exceed 50 Mbit/s.
  • The bandwidth included in each specification is the maximum bandwidth provided by ELB. If the maximum bandwidth is exceeded, the network performance may be affected.