MTU Default and Maximum Values for Physical Interface Modules

Table 7 defines the terms that are used in the context of maximum transmission unit (MTU).

Table 7: MTU Terms

Term

Definition

Physical Interface MTU–Default

Default value of the MTU at the physical interface. The maximum value of the MTU at the physical interface includes the protocol overhead. You can configure the default MTU value at the physical interface by using the following command:
set interface interface-name mtu mtu-value

Logical Interface MTU–Default

Default value of the MTU at the logical interface. The default value is configured at the family level and does not include the protocol overhead. You can configure the default MTU value for each logical unit at the logical interface by using the following command:
set interface interface-name unit interface-unit-number family family-name mtu mtu-value

Maximum MTU

Maximum MTU is the size, measured in bytes, of the largest physical packet that a network can transmit. Any message larger than the MTU is divided into smaller packets before it is sent to its final destination.

Table 8 lists the MTU values for the SRX Series Services Gateway Physical Interface Modules (PIMs).

Table 8: MTU Values for the SRX Series Services Gateway PIMs

PIM

Physical Interface MTU (Bytes)–Default

Logical Interface MTU (Bytes)–Default

Maximum MTU (Bytes)

1–Port Gigabit Ethernet small form-factor pluggable (SFP) Mini-PIM

1514

1500

9010

1–Port small form-factor pluggable (SFP) Mini-PIM

1514

1500

1518

DOCSIS Mini-PIM

1504

1500

1504

Serial Mini-PIM

1504

1500

2000

T1/E1 Mini-PIM

1504

1500

2000

Dual CT1/E1 GPIM

1504

1500

9000

Quad CT1/E1 GPIM

1504

1500

9000

8–Port Serial GPIM

1504

1500

9192

1–Port Clear Channel DS3/E3 GPIM

1504

1500

9192

2–Port 10– Gigabit Ethernet XPIM

1514

1500

9192

8–Port Gigabit Ethernet small form–factor pluggable (SFP) XPIM

1514

1500

9192

16–Port Gigabit Ethernet XPIM

1514

1500

9192

24–Port Gigabit Ethernet XPIM

1514

1500

9192

Table 9 lists maximum transmission unit (MTU) values for ADSL2+ Mini-PIM (Encapsulation), VDSL- Mini-PIM AT mode (Encapsulation), and G.SHDSL Mini-PIM (Encapsulation).

Table 9: MTU Values for ADSL2+ Mini-PIM (Encapsulation), VDSL- Mini-PIM AT mode (Encapsulation), and G.SHDSL Mini-PIM (Encapsulation)

Mini-PIM

Physical Interface MTU (Bytes)–Default

Logical Interface MTU (Bytes)–Default

Maximum MTU (Bytes)

ADSL2+ Mini-PIM (Encapsulation)

atm-snap

1512

1504

1512

atm-vcmux

1512

1512

1512

atm-nlpid

1512

1508

1512

atm-cisco-nlpid

1512

1510

1512

ether-over-atm-llc

1512

1488

1512

atm-ppp-llc

1512

1506

1512

atm-ppp-vcmux

1512

1510

1512

atm-mlppp-llc

1512

1500

1512

ppp-over-ether-over-atm-llc

1512

1480

1512

 

VDSL- Mini-PIM AT mode (Encapsulation)

atm-snap

1514

1506

1514

atm-vcmux

1514

1514

1514

atm-nlpid

1514

1510

1514

atm-cisco-nlpid

1514

1512

1514

ether-over-atm-llc

1514

1490

1524

atm-ppp-llc

1514

1508

1514

atm-ppp-vcmux

1514

1512

1514

atm-mlppp-llc

1514

1500

1514

ppp-over-ether-over-atm-llc

1514

1482

1514

 

VDSL- Mini-PIM PT mode

1514

1500

1514

 

G.SHDSL Mini-PIM (Encapsulation)

atm-snap

4482

4470

4482

atm-vcmux

4482

4470

4482

atm-nlpid

4482

4470

4482

atm-cisco-nlpid

4482

4470

4482

ether-over-atm-llc

4482

1500

4482

atm-ppp-llc

4482

4476

4482

atm-ppp-vcmux

4482

4480

4482

atm-mlppp-llc

4482

1500

4482

ppp-over-ether-over-atm-llc

4482

1492

4482

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