Users Guide

Port Channels:
• All members must have the same link MTU value and the same IP MTU value.
• The port channel link MTU and IP MTU must be less than or equal to the link MTU and IP MTU values congured on the channel
members.
For example, if the members have a link MTU of 2100 and an IP MTU 2000, the port channel’s MTU values cannot be higher than 2100 for
link MTU or 2000 bytes for IP MTU.
VLANs:
• All members of a VLAN must have the same IP MTU value.
• Members can have dierent Link MTU values. Tagged members must have a link MTU 4–bytes higher than untagged members to
account for the packet tag.
• The VLAN link MTU and IP MTU must be less than or equal to the link MTU and IP MTU values congured on the VLAN members.
For example, the VLAN contains tagged members with Link MTU of 1522 and IP MTU of 1500 and untagged members with Link MTU of
1518 and IP MTU of 1500. The VLAN’s Link MTU cannot be higher than 1518 bytes and its IP MTU cannot be higher than 1500 bytes.
Port-Pipes
A port pipe is a Dell Networking-specic term for the hardware packet-processing elements that handle network trac to and from a set of
front-end I/O ports. The physical, front-end I/O ports are referred to as a port-set. In the command-line interface, a port pipe is entered
as port-set port-pipe-number.
CR4 Auto-Negotiation
You can congure interface type as CR4 with auto-negotiation enabled. Many DAC cable link issues are resolved by setting the interface
type as CR4. If the CR4 optic fails to come up, use the
autoneg option.
To congure interface type as CR4 with auto-negotiation enabled, use the following commands.
• Set the interface type as CR4 with auto-negotiation enabled.
INTERFACE mode
intf-type cr4 autoneg
To disable CR4 auto-negotiation, use the no intf-type cr4 autoneg command.
• Verify the conguration.
INTERFACE mode
show config
Example of the intf-type cr4 autoneg Command
Dell(conf)#interface hundredGigE 1/1/1
Dell(conf-if-hu-1/1/1)#intf-type cr4 autoneg
Dell(conf-if-hu-1/1/1)#no intf-type cr4 autoneg
Dell(conf-if-hu-1/1/1)#show config
!
interface hundredGigE 1/1/1
no ip address
shutdown
no intf-type cr4 autoneg
Important Points to Remember
• For 10–Gigabit Ethernet interfaces, CR4 auto-negotiation is not applicable.
• For 100-Gigabit Ethernet interfaces, CR4 auto-negotiation is enabled by default.
• For 40–Gigbit, 25–Gigabit and 50–Gigabit Ethernet interfaces, CR4 auto-negotiation is disabled by default.
Interfaces
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