Cisco MDS 9000 Family NX-OS IP Services Configuration Guide

Configuring Interface Descriptions

See the Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide for details on configuring the switch port description for any interface.

Configuring Beacon Mode

See the Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide for details on configuring the beacon mode for any interface.

Configuring Autonegotiation

By default, autonegotiation is enabled all Gigabit Ethernet interface. You can enable or disable autonegotiation for a specified Gigabit Ethernet interface. When autonegotiation is enabled, the port automatically detects the speed or pause method, and duplex of incoming signals based on the link partner. You can also detect link up conditions using the autonegotiation feature.

To configure autonegotiation, follow these steps:

Note When using DS-SFP-GE-T (copper SFPs) on Gigabit Ethernet interfaces in a DS-X9316-SSNK9 module, auto-negotiation should be disabled.

Configuring the MTU Frame Size

You can configure the interfaces on a switch to transfer large (or jumbo) frames on a port. The default IP maximum transmission unit (MTU) frame size is 1500 bytes for all Ethernet ports. By configuring jumbo frames on a port, the MTU size can be increased up to 9000 bytes.

Note The minimum MTU size is 576 bytes.

Tip MTU changes are disruptive, all FCIP links and iSCSI sessions flap when the software detects a change in the MTU size.

You do not need to explicitly issue the shutdown and no shutdown commands.

To configure the MTU frame size, follow these steps:

Configuring Promiscuous Mode

You can enable or disable promiscuous mode on a specific Gigabit Ethernet interface. By enabling the promiscuous mode, the Gigabit Ethernet interface receives all the packets and the software then filters and discards the packets that are not destined for that Gigabit Ethernet interface.

To configure the promiscuous mode, follow these steps:

About VLANs for Gigabit Ethernet

Virtual LANs (VLANs) create multiple virtual Layer 2 networks over a physical LAN network. VLANs provide traffic isolation, security, and broadcast control.

Gigabit Ethernet ports automatically recognize Ethernet frames with IEEE 802.1Q VLAN encapsulation. If you need to have traffic from multiple VLANs terminated on one Gigabit Ethernet port, configure subinterfaces—one for each VLAN.

Note If the IPS module or MSM-18/4 module is connected to a Cisco Ethernet switch, and you need to have traffic from multiple VLANs coming to one IPS port, verify the following requirements on the Ethernet switch:

• The Ethernet switch port connected to the IPS module or MSM-18/4 module is configured as a trunking port.
• The encapsulation is set to 802.1Q and not ISL, which is the default.

Use the VLAN ID as a subscription to the Gigabit Ethernet interface name to create the subinterface name:

slot-number / port-number.VLAN-ID

Configuring the VLAN Subinterface

To configure a VLAN subinterface (VLAN ID), follow these steps:

Interface Subnet Requirements

Gigabit Ethernet interfaces (major), subinterfaces (VLAN ID), and management interfaces (mgmt 0) can be configured in the same or different subnet depending on the configuration (see Table 7-1 ).

Note The configuration requirements in Table 7-1 also apply to Ethernet PortChannels.

Displaying the IPv4 Route Table

The ip route interface command takes the Gigabit Ethernet interface as a parameter and returns the route table for the interface. See Example 7-2.

Example 7-2 Displays the IP Route Table

Connected (C) identifies the subnet in which the interface is configured (directly connected to the interface). Static (S) identifies the static routes that go through the router.

Gigabit Ethernet IPv4-ACL Guidelines

Follow these guidelines when configuring IPv4-ACLs for Gigabit Ethernet interfaces:

• Only use Transmission Control Protocol (TCP) or Internet Control Message Protocol (ICMP).

Note Other protocols such as User Datagram Protocol (UDP) and HTTP are not supported in Gigabit Ethernet interfaces. Applying an ACL that contains rules for these protocols to a Gigabit Ethernet interface is allowed but those rules have no effect.

• Apply IPv4-ACLs to the interface before you enable an interface. This ensures that the filters are in place before traffic starts flowing.
• Be aware of the following conditions:

– If you use the log-deny option, a maximum of 50 messages are logged per second.

– The established option is ignored when you apply IPv4-ACLs containing this option to Gigabit Ethernet interfaces.

– If an IPv4-ACL rule applies to a pre-existing TCP connection, that rule is ignored. For example if there is an existing TCP connection between A and B and an IPv4-ACL which specifies dropping all packets whose source is A and destination is B is subsequently applied, it will have no effect.

Tip If IPv4-ACLs are already configured in a Gigabit Ethernet interface, you cannot add this interface to an Ethernet PortChannel group. For information on configuring IPv4-ACLs, see the Cisco MDS 9000 Family NX-OS Security Configuration Guide.

Applying IPv4-ACLs on Gigabit Ethernet Interfaces

To apply an IPv4-ACL on a Gigabit Ethernet interface, follow these steps:

Displaying ARP Cache

You can display the ARP cache on Gigabit Ethernet interfaces.

Note Use the physical interface, not the subinterface, for all ARP cache commands.

Use the show ips arp interface gigabitethernet command to display the ARP cache on the Gigabit Ethernet interfaces. This command takes the Ethernet interface as a parameter and returns the ARP cache for that interface. See Example 7-3.

Example 7-3 Displays ARP Caches

Clearing ARP Cache

The ARP cache can be cleared in two ways: clearing just one entry or clearing all entries in the ARP cache.

Use the clear ips arp command to clear the ARP cache. See Example 7-4 and Example 7-5.

Example 7-4 Clearing One ARP Cache Entry

Example 7-5 Clearing All ARP Cache Entries