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Preventing Oversubscription Using Active Physical Ports

 

When oversubscription of Packet Forwarding Capacity is not supported, the demand on each PFE should be less than or equal to its forwarding capacity. To prevent oversubscription, you can configure the number of active ports that operate at the configured speed. Interfaces are created only for active ports. Use this topic for information about the supported active ports on specific line cards.

Supported Active Physical Ports for Configuring Rate Selectability to Prevent Oversubscription

MPC7E-MRATE has an aggregate forwarding capacity of 480 Gbps and a forwarding capacity of 240 Gbps on each Packet Forwarding Engine. Oversubscription of Packet Forwarding Engine capacity is not supported. The demand on each Packet Forwarding Engine must be less than or equal to its forwarding capacity. For instance, on MPC7E-MRATE, the demand on each Packet Forwarding Engine must be less than or equal to 240 Gbps.

Note

By default, the MPC7E-MRATE ports are configured as 10-Gigabit Ethernet ports.

When you configure rate selectability at the MIC level, all the ports supporting that port speed are enabled by default. This can lead to fabric oversubscription in certain cases. To prevent fabric oversubscription, you can configure the number of active ports that operate at the configured speed by using the number-of-ports number-of-active-physical-ports configuration statement. Additionally, interfaces are created only for the active ports.

Note

You cannot configure the number of active ports when you configure rate selectability at the port level.

Table 1 lists the active physical ports on MPC7E-MRATE.

Table 1: Active Physical Ports on MPC7E-MRATE MPC for Configuring Rate Selectability at PIC Level

Ports Configured (number-of-ports Statement)

Active Physical Ports for Different Configured Speeds

10-Gigabit Ethernet

40-Gigabit Ethernet

100-Gigabit Ethernet

1

0

0

2

2

0, 1

0, 1

2, 5

3

0, 1, 2

0, 1, 2

2, 5

4

0, 1, 2, 3

0, 1, 2, 3

2, 5

5

0, 1, 2, 3, 4

0, 1, 2, 3, 4

2, 5

6

0, 1, 2, 3, 4, 5

0, 1, 2, 3, 4, 5

2, 5

MPC8E has a forwarding capacity of 240 Gbps for each Packet Forwarding Engine. MPC9E has a forwarding capacity of 400 Gbps for each Packet Forwarding Engine. Oversubscription of Packet Forwarding Engine capacity is not supported. The demand on each Packet Forwarding Engine must be less than or equal to its forwarding capacity. For instance, on MPC8E, the demand on each Packet Forwarding Engine must be less than or equal to 240 Gbps and on MPC9E, the demand on each Packet Forwarding Engine must be less than or equal to 400 Gbps.

Note

By default, the MIC-MRATE ports are configured as 10-Gigabit Ethernet ports.

Table 2, Table 3 list the active physical ports on MPC8E and MPC9E.

Table 2: Active Physical Ports on MIC-MRATE on MPC8E MPC for Configuring Rate Selectability at MIC Level

Ports Configured (number-of-ports Statement)

Active Physical Ports for Different Configured Speeds

10-Gigabit Ethernet

40-Gigabit Ethernet

100-Gigabit Ethernet

1

0

0

0

2

0, 6

0, 6

0, 6

3

0, 1, 6

0, 1, 6

0, 1, 6

4

0, 1, 6, 7

0, 1, 6, 7

0, 1, 6, 7

5

0, 1, 2, 6, 7

0, 1, 2, 6, 7

0, 1, 6, 7

6

0, 1, 2, 6, 7, 8

0, 1, 2, 6, 7, 8

0, 1, 6, 7

7

0, 1, 2, 3, 6, 7, 8

0, 1, 2, 3, 6, 7, 8

0, 1, 6, 7

8

0, 1, 2, 3, 6, 7, 8, 9

0, 1, 2, 3, 6, 7, 8, 9

0, 1, 6, 7

9

0, 1, 2, 3, 4, 6, 7, 8, 9

0, 1, 2, 3, 4, 6, 7, 8, 9

0, 1, 6, 7

10

0, 1, 2, 3, 4, 6, 7, 8, 9, 10

0, 1, 2, 3, 4, 6, 7, 8, 9, 10

0, 1, 6, 7

11

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

0, 1, 6, 7

12

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11

0, 1, 6, 7

Table 3: Active Physical Ports on MIC-MRATE on MPC9E MPC and MPC8E MPC in 1.6T Mode for Configuring Rate Selectability at MIC Level

Ports Configured (number-of-ports Statement)

Active Physical Ports for Different Configured Speeds

10-Gigabit Ethernet

40-Gigabit Ethernet

100-Gigabit Ethernet

1

0

0

0

2

0, 6

0, 6

0, 6

3

0, 1, 6

0, 1, 6

0, 1, 6

4

0, 1, 6, 7

0, 1, 6, 7

0, 1, 6, 7

5

0, 1, 2, 6, 7

0, 1, 2, 6, 7

0, 1, 2, 6, 7

6

0, 1, 2, 6, 7, 8

0, 1, 2, 6, 7, 8

0, 1, 2, 6, 7, 8

7

0, 1, 2, 3, 6, 7, 8

0, 1, 2, 3, 6, 7, 8

0, 1, 2, 3, 6, 7, 8

8

0, 1, 2, 3, 6, 7, 8, 9

0, 1, 2, 3, 6, 7, 8, 9

0, 1, 2, 3, 6, 7, 8, 9

9

0, 1, 2, 3, 4, 6, 7, 8, 9

0, 1, 2, 3, 4, 6, 7, 8, 9

0, 1, 2, 3, 6, 7, 8, 9

10

0, 1, 2, 3, 4, 6, 7, 8, 9, 10

0, 1, 2, 3, 4, 6, 7, 8, 9, 10

0, 1, 2, 3, 6, 7, 8, 9

11

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

0, 1, 2, 3, 6, 7, 8, 9

12

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11

0, 1, 2, 3, 6, 7, 8, 9

Supported Active Physical Ports for Configuring Rate Selectability to Prevent Oversubscription on MX10003 MPC

When you configure rate selectability at the MIC level, all the ports supporting that port speed are enabled by default. This can lead to fabric oversubscription in certain cases. To prevent fabric oversubscription, you can configure the number of active ports that operate at the configured speed by using the number-of-ports number-of-active-physical-ports configuration statement. Additionally, interfaces are created only for the active ports.

Note

You cannot configure the number of active ports when you configure rate selectability at the port level.

Starting in Junos OS Release 17.3R1, the MX10003 MPC supports rate selectability to prevent oversubscription of the Packet Forwarding Engine bandwidth.

Table 4 lists the active physical ports on MX10003 MPC for Configuring Rate Selectability at the MIC Level.

Table 4: Active Physical Ports on the MX10003 MPC for configuring rate selectability at the MIC level

Ports Configured (number-of-ports Statement)

Active Physical Ports for Different Configured Speeds

10-Gigabit Ethernet

40-Gigabit Ethernet

100-Gigabit Ethernet

1

0

0

0

2

0, 4

0, 4

0, 4

3

0, 4, 8

0, 4, 8

0, 4, 8

4

0, 1, 4, 8

0, 1, 4, 8

0, 1, 4, 8

5

0, 1, 4, 5, 8

0, 1, 4, 5, 8

0, 1, 4, 5, 8

6

0, 1, 4, 5, 8, 9

0, 1, 4, 5, 8, 9

0, 1, 4, 5, 8, 9

7

0, 1, 2, 4, 5, 8, 9

0, 1, 2, 4, 5, 8, 9

0, 1, 2, 4, 5, 8, 9

8

0, 1, 2, 4, 5, 6, 8, 9

0, 1, 2, 4, 5, 6, 8, 9

0, 1, 2, 4, 5, 6, 8, 9

9

0, 1, 2, 4, 5, 6, 8, 9, 10

0, 1, 2, 4, 5, 6, 8, 9, 10

0, 1, 2, 4, 5, 6, 8, 9, 10

10

0, 1, 2, 3, 4, 5, 6, 8, 9, 10

0, 1, 2, 3, 4, 5, 6, 8, 9, 10

0, 1, 2, 3, 4, 5, 6, 8, 9, 10

11

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

12

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11

Table 5 list the active physical ports on MX10003 MPC for Configuring Rate Selectability at PIC Level.

Table 5: Active Physical Ports on MX10003 MPC for configuring rate selectability at the PIC level

Ports Configured (number-of-ports Statement)

Active Physical Ports for Different Configured Speeds

10-Gigabit Ethernet

40-Gigabit Ethernet

1

0

0

2

0, 2

0, 2

3

0, 2, 4

0, 2, 4

4

0, 1, 2, 4

0, 1, 2, 4

5

0, 1, 2, 3, 4

0, 1, 2, 3, 4

6

0, 1, 2, 3, 4, 5

0, 1, 2, 3, 4, 5

Supported Active Physical Rate-Selectable Ports to Prevent Oversubscription on MX204 Router

The maximum capacity of an MX204 router is 400 Gbps, which cannot be oversubscribed. In MX204, the network ports are available in two groups (referred to as PICs), with restrictions around the number and type of ports that can be configured without oversubscribtion.

Starting in Junos OS Release 17.4R1, the MX204 supports rate selectability to prevent oversubscription of the Packet Forwarding Engine bandwidth. The MX204 Packet Forwarding Engine has four 100-Gigabit Ethernet QSFP28 ports (referred to as PIC 0 ports) and eight 10-Gigabit Ethernet ports (referred to as PIC 1 ports). Each of the PIC 0 ports can be used as either a 100-Gigabit Ethernet QSFP28 port or a 40-Gigabit Ethernet QSFPP port, or they can be configured as four 10-Gigabit Ethernet ports (using a breakout cable).

If you configure rate selectability at the PIC level, all the ports supporting that port speed are enabled by default. This can lead to oversubscription in certain cases. To prevent the oversubscription, you can configure the number of active ports that operate at the configured speed by using the number-of-ports number-of-active-physical-ports configuration statement. Additionally, interfaces are created only for the active ports.

Note
  • You cannot configure the number of active ports when you configure rate selectability at the port level.

Invalid Port Configuration

You must try to avoid configuring ports that can lead to oversubscription.

Following is an example of an invalid configuration:

If you try to commit an invalid configuration, the configuration gets committed, but the port is not activated. This is because Junos OS allows you to configure a port before a line card is inserted. You will get an error message in the output of the show chassis alarms command and also in the log messages.

Note

When you are in port configuration mode, all the ports are configured as 10-Gigabit Ethernet.

Configuring Active Ports on MX204 Router with Rate Selectability

Table 6 summarizes the active ports with number-of-ports configured but without any rate selectability configuration for an MX204 router. Because there is no rate selectability configured, the default speed is used in these cases.

Table 6: Active Physical Ports on the MX204 Router for Configuring Rate Selectability at PIC level

PIC

Number of Ports (number-of-ports Statement)

Active Ports

PIC Level 10-Gigabit Ethernet Profile

PIC Level 40-Gigabit Ethernet Profile

PIC Level 100-Gigabit Ethernet Profile

PIC 0

0

-

-

-

1

0

-

-

2

0, 1

-

-

3

0, 1, 2

-

-

4

0, 1, 2, 3

-

-

PIC 1

0

-

-

-

1

0

-

-

2

0, 1

-

-

3

0, 1, 2

-

-

4

0, 1, 2, 3

-

-

5

0, 1, 2, 3, 4

-

-

6

0, 1, 2, 3, 4, 5

-

-

7

0, 1, 2, 3, 4, 5 ,6

-

-

8

0, 1, 2, 3, 4, 5, 6, 7

-

-

Table 7 summarizes the active ports without number-of-ports configured but with rate selectability at PIC-level configuration for an MX204 router.

Table 7: Without number-of-ports But with Rate Selectability at PIC Level for MX204 Router

PIC

Active Ports

PIC-Level 10-Gigabit Ethernet

PIC-Level 40-Gigabit Ethernet

PIC-Level 100-Gigabit Ethernet

PIC 0

0-3

0-3

0-3

PIC 1

0-7

-

-

Table 8 summarizes the active ports with number-of-ports configured and rate selectability at PIC-level configuration for an MX204 router.

Table 8: With number-of-ports Rate Selectability at PIC level for MX204 Router

PIC

Number of Ports (number-of-ports Statement)

Active Ports

PIC-Level 10-Gigabit Ethernet

PIC-Level 40-Gigabit Ethernet

PIC-Level 100-Gigabit Ethernet

PIC 0

0

-

-

-

1

0

0

0

2

0, 1

0, 1

0, 1

3

0, 1, 2

0, 1, 2

0, 1, 2

4

0, 1, 2, 3

0, 1, 2, 3

0, 1, 2, 3

PIC 1

0

-

-

-

1

0

-

-

2

0, 1

-

-

3

0, 1, 2

-

-

4

0, 1, 2, 3

-

-

5

0, 1, 2, 3, 4

-

-

6

0, 1, 2, 3, 4, 5

-

-

7

0, 1, 2, 3, 4, 5 ,6

-

-

8

0, 1, 2, 3, 4, 5, 6, 7

-

-

Supported Active Physical Ports for Rate Selectability to Prevent Oversubscription on MPC10E-15C-MRATE

When you configure speed at the PIC level, all the ports supporting that port speed are enabled by default. This could lead to Packet Forwarding Engine (PFE) oversubscription. To prevent oversubscription, configure the number of active ports that operate at the configured speed by using the number-of-ports number-of-active-physical-ports configuration statement. Additionally, interfaces are created only for the active ports.

Note

You cannot configure the number of active ports when you configure rate at the port level.

Starting in Junos OS Release 19.1R1, the MPC10E-15C-MRATE supports rate selectability to prevent oversubscription of the PFE bandwidth.

Table 9 summarizes the active ports with number-of-ports and without any rate selectability configuration for MPC10E-15C-MRATE. Because there is no rate selectability configured, the default mode and no pic-mode configuration is applied.

Table 9: Active Ports with number-of-ports and without rate-selectability

Number of Active Ports

Active Ports with PIC level rate selectability

10-Gigabit Ethernet

40-Gigabit Ethernet

100-Gigabit Ethernet

1

-

-

0

2

-

-

0, 1

3

-

-

0, 1, 2

4

-

-

0, 1, 2, 3

5

-

-

0, 1, 2, 3, 4

Table 10 list the active ports without number-of-ports and with rate selectability at PIC level for MPC10E-15C-MRATE.

Table 10: Active Ports without number-of-ports and with speed configured at PIC level

PIC Type

Active Ports with speed configured at PIC level

10-Gigabit Ethernet

40-Gigabit Ethernet

100-Gigabit Ethernet

5xQSFP28 PIC (PIC 0)

0, 1, 2, 3, 4

0, 1, 2, 3, 4

0, 1, 2, 3, 4

5xQSFP28 PIC (PIC 1)

0, 1, 2, 3, 4

0, 1, 2, 3, 4

0, 1, 2, 3, 4

5xQSFP28 PIC (PIC 2)

0, 1, 2, 3, 4

0, 1, 2, 3, 4

0, 1, 2, 3, 4

Table 11 list the active ports with number-of-ports and rate selectability at PIC level for MPC10E-15C-MRATE.

Table 11: Active Ports with number-of-ports and rate selectability at PIC level

PIC Type

Number of Active Ports

Active Ports with speed configured at PIC level

10-Gigabit Ethernet

40-Gigabit Ethernet

100-Gigabit Ethernet

5xQSFP28 PIC (PIC 0)

1

0

0

0

2

0, 1

0, 1

0, 1

3

0, 1, 2

0, 1, 2

0, 1, 2

4

0, 1, 2, 3

0, 1, 2, 3

0, 1, 2, 3

5

0, 1, 2, 3, 4

0, 1, 2, 3, 4

0, 1, 2, 3, 4

5xQSFP28 PIC (PIC 1)

1

0

0

0

2

0, 1

0, 1

0, 1

3

0, 1, 2

0, 1, 2

0, 1, 2

4

0, 1, 2, 3

0, 1, 2, 3

0, 1, 2, 3

5

0, 1, 2, 3, 4

0, 1, 2, 3, 4

0, 1, 2, 3, 4

5xQSFP28 PIC (PIC 2)

1

0

0

0

2

0, 1

0, 1

0, 1

3

0, 1, 2

0, 1, 2

0, 1, 2

4

0, 1, 2, 3

0, 1, 2, 3

0, 1, 2, 3

5

0, 1, 2, 3, 4

0, 1, 2, 3, 4

0, 1, 2, 3, 4

Supported Active Physical Ports for Rate Selectability to Prevent Oversubscription on MPC10E-10C-MRATE

When you configure speed at the PIC level, all the ports supporting that port speed are enabled by default. This could lead to Packet Forwarding Engine (PFE) oversubscription. To prevent oversubscription, configure the number of active ports that operate at the configured speed by using the number-of-ports number-of-active-physical-ports configuration statement. Additionally, interfaces are created only for the active ports.

Note

You cannot configure the number of active ports when you configure rate at the port level.

Starting in Junos OS Release 19.2R1, the MPC10E-10C-MRATE supports rate selectability to prevent oversubscription of the PFE bandwidth.

Table 12 summarizes the active ports with number-of-ports and without any rate selectability configuration for MPC10E-10C-MRATE. Because there is no rate selectability configured, the default mode and no pic-mode configuration is applied.

Table 12: Active Ports with number-of-ports and without rate-selectability

Number of Active Ports

Active Ports with PIC level rate selectability

10-Gigabit Ethernet

40-Gigabit Ethernet

100-Gigabit Ethernet

1

-

-

0

2

-

-

0, 1

3

-

-

0, 1, 2

4

-

-

0, 1, 2, 3

5

-

-

0, 1, 2, 3, 4

Table 13 lists the active ports without number-of-ports and with rate selectability at PIC level for MPC10E-10C-MRATE.

Table 13: Active Ports without number-of-ports and with speed configured at PIC level

PIC Type

Active Ports with speed configured at PIC level

10-Gigabit Ethernet

40-Gigabit Ethernet

100-Gigabit Ethernet

5xQSFP28 PIC (PIC 0)

0, 1, 2, 3, 4

0, 1, 2, 3, 4

0, 1, 2, 3, 4

5xQSFP28 PIC (PIC 1)

0, 1, 2, 3, 4

0, 1, 2, 3, 4

0, 1, 2, 3, 4

Table 14 lists the active ports with number-of-ports and rate selectability at PIC level for MPC10E-10C-MRATE.

Table 14: Active Ports with number-of-ports and rate selectability at PIC level

PIC Type

Number of Active Ports

Active Ports with speed configured at PIC level

10-Gigabit Ethernet

40-Gigabit Ethernet

100-Gigabit Ethernet

5xQSFP28 PIC (PIC 0)

1

0

0

0

2

0, 1

0, 1

0, 1

3

0, 1, 2

0, 1, 2

0, 1, 2

4

0, 1, 2, 3

0, 1, 2, 3

0, 1, 2, 3

5

0, 1, 2, 3, 4

0, 1, 2, 3, 4

0, 1, 2, 3, 4

5xQSFP28 PIC (PIC 1)

1

0

0

0

2

0, 1

0, 1

0, 1

3

0, 1, 2

0, 1, 2

0, 1, 2

4

0, 1, 2, 3

0, 1, 2, 3

0, 1, 2, 3

5

0, 1, 2, 3, 4

0, 1, 2, 3, 4

0, 1, 2, 3, 4