Fip Virtual Link Instantiation; Fcoe Frame Format; Vlan Tagging For Fcoe Frames - Cisco AP775A - Nexus Converged Network Switch 5010 Configuration Manual

FIP Virtual Link Instantiation

• FIP—The Converged Enhanced Ethernet Data Center Bridging Exchange (CEE-DCBX) protocol supports
• Pre-FIP—The Cisco, Intel, Nuova Data Center Bridging Exchange (CIN-DCBX) protocol supports
The Cisco Nexus 5000 Series switch detects the capabilities of the attached CNA and switches to the correct
FIP mode.
FIP Virtual Link Instantiation
Cisco NX-OS Release 4.1(3)N1(1) adds support for the T11-compliant FIP on the Cisco Nexus 5000 Series
switch.
FIP is used to perform device discovery, initialization, and link maintenance. FIP performs the following
protocols:
• FIP Discovery—When a FCoE device is connected to the fabric, it sends out a Discovery Solicitation
• FCoE Virtual Link instantiation— FIP defines the encapsulation of fabric login (FLOGI) , fabric discovery
• FCoE Virtual Link maintenance— FIP periodically sends maintenance messages between the switch

FCoE Frame Format

FCoE is encapsulated in an Ethernet packet with a dedicated EtherType, 0x8906. That packet has a 4-bit
version field. The other header fields in the frame (the source and destination MAC addresses, VLAN tags,
and frame markers) are all standard Ethernet fields. Reserved bits pad the FCoE frame to the IEEE 802.3
minimum packet length of 64 bytes.
A Fibre Channel frame consists of 36 bytes of headers and up to 2112 bytes of data for a total maximum size
of 2148 bytes. The encapsulated Fibre Channel frame has all the standard headers, which allow it to be passed
to the storage network without further modification. To accomodate the maximum Fibre Channel frame in an
FC0E frame, the class-fcoe is defined with a default MTU of 2240 bytes.

VLAN Tagging for FCoE Frames

The Ethernet frames that are sent by the switch to the adapter may include the IEEE 802.1Q tag. This tag
includes a field for the class of service (CoS) value used by the priority flow control (PFC). The IEEE 802.1Q
tag also includes a VLAN field.
The Cisco Nexus 5000 Series switch expects frames from a FIP T11-compliant CNA to be tagged with the
VLAN tag for the FCoE VLAN. Frames that are not correctly tagged are discarded.
The switch expects frames from a pre-FIP CNA to be priority tagged with the FCoE CoS value. The switch
will still accept untagged frames from the CNA.
Cisco Nexus 5000 Series Switch CLI Software Configuration Guide
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T11-compliant Gen-2 CNAs.
Gen-1 converged network adapters (CNAs).
message. A Fibre Channel Forwarder (FCF) or a switch responds to the message with a Solicited
Advertisement that provides an FCF MAC address to use for subsequent logins.
(FDISC), logout (LOGO), and exchange link parameters (ELP) frames along with the corresponding
reply frames. The FCoE devices use these messages to perform a fabric login.
and the CNA to ensure the connection is still valid.
Information About FCoE
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