- Preface
- New and Changed Information
- Overview
-
- Configuring Ethernet Interfaces
- Configuring VLANs
- Configuring Private VLANs
- Configuring Access and Trunk Interfaces
- Configuring EtherChannels
- Configuring Virtual Port Channels
- Configuring Rapid PVST+
- Configuring Multiple Spanning Tree
- Configuring STP Extensions
- Configuring the MAC Address Table
- Configuring IGMP Snooping
- Configuring Traffic Storm Control
-
- Configuring Fibre Channel Interfaces
- Configuring Domain Parameters
- Configuring N Port Virtualization
- Configuring VSAN Trunking
- Configuring SAN Port Channel
- Configuring and Managing VSANs
- Configuring and Managing Zones
- Distributing Device Alias Services
- Configuring Fibre Channel Routing Services and Protocols
- Managing FLOGI, Name Server, FDMI, and RSCN Databases
- Discovering SCSI Targets
- Advanced Fibre Channel Features and Concepts
- Configuring FC-SP and DHCHAP
- Configuring Port Security
- Configuring Fabric Binding
- Configuring Fabric Configuration Servers
- Configuring Port Tracking
- Configuration Limits
- Index
Contents
- Configuring Fibre Channel Interfaces
- Configuring Fibre Channel Interfaces
- Information About Fibre Channel Interfaces
- Licensing Requirements for Fibre Channel
- Physical Fibre Channel Interfaces
- Virtual Fibre Channel Interfaces
- Interface Modes
- E Port
- F Port
- NP Port
- TE Port
- SD Port
- Auto Mode
- Interface States
- Administrative States
- Operational States
- Reason Codes
- Buffer-to-Buffer Credits
- Configuring Fibre Channel Interfaces
- Configuring a Fibre Channel Interface
- Configuring a Range of Fibre Channel Interfaces
- Setting the Interface Administrative State
- Configuring Interface Modes
- Configuring the Interface Description
- Configuring Port Speeds
- Autosensing
- Configuring SD Port Frame Encapsulation
- Configuring Receive Data Field Size
- Understanding Bit Error Thresholds
- Configuring Buffer-to-Buffer Credits
- Configuring Global Attributes for Fibre Channel Interfaces
- Configuring Switch Port Attribute Default Values
- About N Port Identifier Virtualization
- Enabling N Port Identifier Virtualization
- Verifying Fibre Channel Interfaces
- Verifying SFP Transmitter Types
- Verifying Interface Information
- Verifying BB_Credit Information
- Default Fibre Channel Interface Settings
Configuring Fibre Channel Interfaces
This chapter contains the following sections:
Configuring Fibre Channel Interfaces
Information About Fibre Channel Interfaces
Licensing Requirements for Fibre Channel
On Cisco Nexus 5000 Series switches, Fibre Channel capability is included in the Storage Protocol Services license.
Ensure that you have the correct license installed (N5010SS or N5020SS) before using Fibre Channel interfaces and capabilities.
 Note | You can configure virtual Fibre Channel interfaces without a Storage Protocol Services license, but these interfaces will not become operational until the license is activated. |
Physical Fibre Channel Interfaces
Cisco Nexus 5000 Series switches provide up to sixteen physical Fibre Channel uplinks. The Fibre Channel interfaces are supported on optional expansion modules. The Fibre Channel expansion module contains eight Fibre Channel interfaces. The Fibre Channel plus Ethernet expansion module contains four Fibre Channel interfaces.
Each Fibre Channel port can be used as a downlink (connected to a server) or as an uplink (connected to the data center SAN network). The Fibre Channel interfaces support the following modes: F, NP, E, TE, and SD.
Virtual Fibre Channel Interfaces
Fibre Channel over Ethernet (FCoE) encapsulation allows a physical Ethernet cable to simultaneously carry Fibre Channel and Ethernet traffic. In Cisco Nexus 5000 Series switches, an FCoE-capable physical Ethernet interface can carry traffic for one virtual Fibre Channel interface.
Native Fibre Channel and virtual Fibre Channel interfaces are configured using the same CLI commands. Virtual Fibre Channel interfaces support only F mode, and offer a subset of the features that are supported on native Fibre Channel interfaces.
The following capabilities are not supported for virtual Fibre Channel interfaces:
-
SAN port channels.
-
VSAN trunking. The virtual Fibre Channel is associated with one VSAN.
-
The SPAN destination cannot be a virtual Fibre Channel interface.
-
Buffer-to-buffer credits.
-
Exchange link parameters (ELP), or Fabric Shortest Path First (FSPF) protocol.
-
Configuration of physical attributes (speed, rate, mode, transmitter information, MTU size).
-
Port tracking.
Interface Modes
Each physical Fibre Channel interface in a switch may operate in one of several port modes: E mode, TE mode, F mode, and SD mode (see the figure below). A physical Fibre Channel interface can be configured as an E port, an F port, or an SD port. Interfaces may also be configured in Auto mode; the port type is determined during interface initialization.
In NPV mode, Fibre Channel interfaces may operate in NP mode, F mode or SD mode.
Virtual Fibre Channel interfaces can only be configured in F mode.
Note | Interfaces are automatically assigned VSAN 1 by default. |
Each interface has an associated administrative configuration and an operational status:
-
The administrative configuration does not change unless you modify it. This configuration has various attributes that you can configure in administrative mode.
-
The operational status represents the current status of a specified attribute such as the interface speed. This status cannot be changed and is read-only. Some values may not be valid when the interface is down (for example, the operational speed).
E Port
In expansion port (E port) mode, an interface functions as a fabric expansion port. This port may be connected to another E port to create an Inter-Switch Link (ISL) between two switches. E ports carry frames between switches for configuration and fabric management. They serve as a conduit between switches for frames destined to remote N ports. E ports support class 3 and class F service.
An E port connected to another switch may also be configured to form a SAN port channel.
F Port
In fabric port (F port) mode, an interface functions as a fabric port. This port may be connected to a peripheral device (host or disk) operating as a node port (N port). An F port can be attached to only one N port. F ports support class 3 service.
NP Port
When the switch is operating in NPV mode, the interfaces that connect the switch to the core network switch are configured as NP ports. NP ports operate like N ports that function as proxies for multiple physical N ports.
TE Port
In trunking E port (TE port) mode, an interface functions as a trunking expansion port. It may be connected to another TE port to create an extended ISL (EISL) between two switches. TE ports connect to another Cisco Nexus 5000 Series switch or a Cisco MDS 9000 Family switch. They expand the functionality of E ports to support the following:
In TE port mode, all frames are transmitted in EISL frame format, which contains VSAN information. Interconnected switches use the VSAN ID to multiplex traffic from one or more VSANs across the same physical link. This feature is referred to as VSAN trunking in the Cisco Nexus 5000 Series switch. TE ports support class 3 and class F service.
SD Port
In SPAN destination port (SD port) mode, an interface functions as a switched port analyzer (SPAN). The SPAN feature monitors network traffic that passes though a Fibre Channel interface. This monitoring is done using a standard Fibre Channel analyzer (or a similar switch probe) that is attached to an SD port. SD ports do not receive frames, instead they transmit a copy of the source traffic. The SPAN feature is nonintrusive and does not affect switching of network traffic for any SPAN source ports.
Auto Mode
Interfaces configured in auto mode can operate in one of the following modes: F port, E port, or TE port. The port mode is determined during interface initialization. For example, if the interface is connected to a node (host or disk), it operates in F port mode. If the interface is attached to a third-party switch, it operates in E port mode. If the interface is attached to another switch in the Cisco Nexus 5000 Series or Cisco MDS 9000 Family, it may become operational in TE port mode.
SD ports are not determined during initialization and are administratively configured.
Interface States
The interface state depends on the administrative configuration of the interface and the dynamic state of the physical link.
Administrative States
The administrative state refers to the administrative configuration of the interface. The table below describes the administrative states.
|
Administrative State |
Description |
|---|---|
|
Up |
Interface is enabled. |
|
Down |
Interface is disabled. If you administratively disable an interface by shutting down that interface, the physical link layer state change is ignored. |
Operational States
The operational state indicates the current operational state of the interface. The table below describes the operational states.
|
Operational State |
Description |
|---|---|
|
Up |
Interface is transmitting or receiving traffic as desired. To be in this state, an interface must be administratively up, the interface link layer state must be up, and the interface initialization must be completed. |
|
Down |
Interface cannot transmit or receive (data) traffic. |
|
Trunking |
Interface is operational in TE mode. |
Reason Codes
Reason codes are dependent on the operational state of the interface. The following table describes the reason codes for operational states.
|
Administrative Configuration |
Operational Status |
Reason Code |
|---|---|---|
|
Up |
Up |
None. |
|
Down |
Down |
Administratively down. If you administratively configure an interface as down, you disable the interface. No traffic is received or transmitted. |
|
Up |
Down |
See the table below. |
If the administrative state is up and the operational state is down, the reason code differs based on the nonoperational reason code. The table below describes the reason codes for nonoperational states.
Note | Only some of the reason codes are listed in the table. |
Buffer-to-Buffer Credits
Buffer-to-buffer credits (BB_credits) are a flow-control mechanism to ensure that Fibre Channel interfaces do not drop frames. BB_credits are negotiated on a per-hop basis.
In Cisco Nexus 5000 Series switches, the BB_credit mechanism is used on Fibre Channel interfaces but not on virtual Fibre Channel interfaces. Virtual Fibre Channel interfaces provide flow control based on capabilities of the underlying physical Ethernet interface.
The receive BB_credit value (fcrxbbcredit) may be configured for each Fibre Channel interface. In most cases, you do not need to modify the default configuration.
Note | The receive BB_credit values depend on the port mode. For physical Fibre Channel interfaces, the default value is 16 for F mode and E mode interfaces. This value can be changed as required. The maximum value is 64. For virtual Fibre Channel interfaces, BB_credits are not used. |
Configuring Fibre Channel Interfaces
Configuring a Fibre Channel Interface
To configure a Fibre Channel interface, perform this task:
1.
switch# configuration terminal
2.
switch(config)# interface {fc
slot/port}|{vfc
vfc-id}
DETAILED STEPS
Configuring a Range of Fibre Channel Interfaces
To configure a range of Fibre Channel interfaces, perform this task:
1.
switch# configuration terminal
2.
switch(config)# interface { fc
slot/port - port [ , fc
slot/port - port ] | vfc
vfc-id - vfc-id [ , vfc
vfc-id - vfc-id ] }
DETAILED STEPS
| Command or Action | Purpose |
|---|
Setting the Interface Administrative State
To gracefully shut down an interface, perform this task:
To enable traffic flow, perform this task:
1.
switch# configuration terminal
2.
switch(config)# interface {fc
slot/port}|{vfc
vfc-id}
3.
switch(config-if)# shutdown
DETAILED STEPS
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
switch# configuration terminal
|
Enters configuration mode. |
| Step 2 |
switch(config)# interface {fc
slot/port}|{vfc
vfc-id}
|
Selects a Fibre Channel interface and enters interface configuration mode. |
| Step 3 |
switch(config-if)# shutdown
|
Gracefully shuts down the interface and administratively disables traffic flow (default). |
Configuring Interface Modes
To configure the interface mode, perform this task:
1.
switch# configuration terminal
2.
switch(config)# interface {fc
slot/port}|{vfc
vfc-id}
3.
switch(config-if)# switchport mode
E | F | SD | auto
DETAILED STEPS
| Command or Action | Purpose | |||
|---|---|---|---|---|
| Step 1 |
switch# configuration terminal
|
Enters configuration mode. | ||
| Step 2 |
switch(config)# interface {fc
slot/port}|{vfc
vfc-id}
|
Selects a Fibre Channel interface and enters interface configuration mode. | ||
| Step 3 |
switch(config-if)# switchport mode
E | F | SD | auto
|
For a Fibre Channel interface, you can set the mode to E, F, or SD port mode. Set the mode to auto to auto-negotiate an E, F, TE port mode (not SD port mode) of operation.
For a virtual Fibre Channel, only the F port mode is supported. |
Configuring the Interface Description
Interface descriptions should help you identify the traffic or use for that interface. The interface description can be any alphanumeric string.
To configure a description for an interface, perform this task:
1.
switch# configuration terminal
2.
switch(config)# interface {fc
slot/port}|{vfc
vfc-id}
3.
switch(config-if)# switchport description cisco-HBA2
4.
switch(config-if)# no switchport description
DETAILED STEPS
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
switch# configuration terminal
|
Enters configuration mode. |
| Step 2 |
switch(config)# interface {fc
slot/port}|{vfc
vfc-id}
|
Selects a Fibre Channel interface and enters interface configuration mode. |
| Step 3 |
switch(config-if)# switchport description cisco-HBA2
|
Configures the description of the interface. The string can be up to 80 characters long. |
| Step 4 |
switch(config-if)# no switchport description
|
Clears the description of the interface. |
Configuring Port Speeds
Port speed can be configured on a physical Fibre Channel interface but not on a virtual Fibre Channel interface. By default, the port speed for an interface is automatically calculated by the switch.
 Caution | Changing the interface speed is a disruptive operation. |
To configure the port speed of the interface, perform this task:
1.
switch# configuration terminal
2.
switch(config)# interface fc
slot/port
3.
switch(config-if)# switchport speed 1000
4.
switch(config-if)# no switchport speed
DETAILED STEPS
| Command or Action | Purpose | |||
|---|---|---|---|---|
| Step 1 |
switch# configuration terminal
|
Enters configuration mode. | ||
| Step 2 |
switch(config)# interface fc
slot/port
|
Selects the specified interface and enters interface configuration mode.
| ||
| Step 3 |
switch(config-if)# switchport speed 1000
|
Configures the port speed of the interface to 1000 Mbps. The number indicates the speed in megabits per second (Mbps). You can set the speed to 1000 (for 1-Gbps interfaces), 2000 (for 2-Gbps interfaces), 4000 (for 4-Gbps interfaces), or auto (default). | ||
| Step 4 |
switch(config-if)# no switchport speed
|
Reverts to the factory default (auto) administrative speed of the interface. |
Autosensing
Autosensing speed is enabled on all 4-Gbps interfaces by default. This configuration enables the interfaces to operate at speeds of 1 Gbps, 2 Gbps, or 4 Gbps on the 4-Gbps ports. When autosensing is enabled for an interface operating in dedicated rate mode, 4-Gbps of bandwidth is reserved, even if the port negotiates at an operating speed of 1-Gbps or 2-Gbps.
Configuring SD Port Frame Encapsulation
The switchport encap eisl command only applies to SD port interfaces. This command determines the frame format for all frames transmitted by the interface in SD port mode. If the encapsulation is set to EISL, all outgoing frames are transmitted in the EISL frame format, for all SPAN sources.
The switchport encap eisl command is disabled by default. If you enable encapsulation, all outgoing frames are encapsulated, and you will see a new line (Encapsulation is eisl) in the show interface SD_port_interface command output.
Configuring Receive Data Field Size
You can configure the receive data field size for native Fibre Channel interfaces (but not for virtual Fibre Channel interfaces). If the default data field size is 2112 bytes, the frame length will be 2148 bytes.
To configure the receive data field size, perform this task:
1.
switch# configuration terminal
2.
switch(config)# interface fc
slot/port
3.
switch(config-if)# switchport fcrxbufsize 2000
DETAILED STEPS
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
switch# configuration terminal
|
Enters configuration mode. |
| Step 2 |
switch(config)# interface fc
slot/port
|
Selects a Fibre Channel interface and enters interface configuration mode. |
| Step 3 |
switch(config-if)# switchport fcrxbufsize 2000
|
Reduces the data field size for the selected interface to 2000 bytes. The default is 2112 bytes and the range is from 256 to 2112 bytes. |
Understanding Bit Error Thresholds
The bit error rate threshold is used by the switch to detect an increased error rate before performance degradation seriously affects traffic.
The bit errors can occur for the following reasons:
- Faulty or bad cable.
- Faulty or bad GBIC or SFP.
- GBIC or SFP is specified to operate at 1 Gbps but is used at 2 Gbps.
- GBIC or SFP is specified to operate at 2 Gbps but is used at 4 Gbps.
- Short haul cable is used for long haul or long haul cable is used for short haul.
- Momentary synchronization loss.
- Loose cable connection at one or both ends.
- Improper GBIC or SFP connection at one or both ends.
A bit error rate threshold is detected when 15 error bursts occur in a 5-minute period. By default, the switch disables the interface when the threshold is reached.
You can enter the shutdown/no shutdown command sequence to reenable the interface.
You can configure the switch to not disable an interface when the threshold is crossed.
Note | The switch generates a syslog message when bit error threshold events are detected, even if the interface is configured not to be disabled by bit-error threshold events. |
To disable the bit error threshold for an interface, perform this task:
1.
switch#
configuration terminal
2.
switch(config)#
interface fc
slot/port
3.
switch(config-if)#
switchport ignore
bit-errors
4.
switch(config-if)#
no switchport ignore
bit-errors
DETAILED STEPS
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
switch#
configuration terminal
|
Enters configuration mode. |
| Step 2 |
switch(config)#
interface fc
slot/port
|
Selects a Fibre Channel interface and enters interface configuration mode. |
| Step 3 |
switch(config-if)#
switchport ignore
bit-errors
|
Prevents the detection of bit error threshold events from disabling the interface. |
| Step 4 |
switch(config-if)#
no switchport ignore
bit-errors
|
Prevents the detection of bit error threshold events from enabling the interface. |
Configuring Buffer-to-Buffer Credits
To configure BB_credits for a Fibre Channel interface, perform this task:
1.
switch# configuration terminal
2.
switch(config)# interface fc
slot/port
3.
switch(config-if)# switchport fcrxbbcredit default
4.
switch(config-if)# switchport fcrxbbcredit 5
5.
switch(config-if)# switchport fcrxbbcredit 5 mode E
6.
switch(config-if)# switchport fcrxbbcredit 5 mode Fx
7.
switch(config-if# do show int fc
slot/port
DETAILED STEPS
| Command or Action | Purpose | |||
|---|---|---|---|---|
| Step 1 |
switch# configuration terminal
|
Enters configuration mode. | ||
| Step 2 |
switch(config)# interface fc
slot/port
|
Selects a Fibre Channel interface and enters interface configuration mode. | ||
| Step 3 |
switch(config-if)# switchport fcrxbbcredit default
|
Applies the default operational value to the selected interface. The operational value depends on the port mode. The default values are assigned based on the port capabilities. | ||
| Step 4 |
switch(config-if)# switchport fcrxbbcredit 5
|
Assigns a BB_credit of 5 to the selected interface. The range to assign BB_credits is between 1 and 64. | ||
| Step 5 |
switch(config-if)# switchport fcrxbbcredit 5 mode E
|
Assigns this value if the port is operating in E or TE mode. The range to assign BB_credits is between 1 and 64. | ||
| Step 6 |
switch(config-if)# switchport fcrxbbcredit 5 mode Fx
|
Assigns this value if the port is operating in F mode. The range to assign BB_credits is between 1 and 64. | ||
| Step 7 |
switch(config-if# do show int fc
slot/port
|
Displays the receive and transmit BB_credit along with other pertinent interface information for this interface.
|
Configuring Global Attributes for Fibre Channel Interfaces
Configuring Switch Port Attribute Default Values
You can configure attribute default values for various switch port attributes. These attributes will be applied globally to all future switch port configurations, even if you do not individually specify them at that time.
To configure switch port attributes, perform this task:
1.
switch# configuration terminal
2.
switch(config)# no system default switchport shutdown san
3.
switch(config)# system default switchport shutdown san
4.
switch(config)# system default switchport trunk mode auto
DETAILED STEPS
| Command or Action | Purpose | |||
|---|---|---|---|---|
| Step 1 |
switch# configuration terminal
|
Enters configuration mode. | ||
| Step 2 |
switch(config)# no system default switchport shutdown san
|
Configures the default setting for administrative state of an interface as Up. (The factory default setting is Down).
| ||
| Step 3 |
switch(config)# system default switchport shutdown san
|
Configures the default setting for administrative state of an interface as Down. This is the factory default setting.
| ||
| Step 4 |
switch(config)# system default switchport trunk mode auto
|
Configures the default setting for administrative trunk mode state of an interface as Auto.
|
About N Port Identifier Virtualization
N port identifier virtualization (NPIV) provides a means to assign multiple FC IDs to a single N port. This feature allows multiple applications on the N port to use different identifiers and allows access control, zoning, and port security to be implemented at the application level. The following figure shows an example application using NPIV.
Enabling N Port Identifier Virtualization
To enable or disable NPIV on the switch, perform this task:
You must globally enable NPIV for all VSANs on the switch to allow the NPIV-enabled applications to use multiple N port identifiers.
Note | All of the N port identifiers are allocated in the same VSAN. |
1.
switch# configuration terminal
2.
switch(config)# feature npiv
3.
switch(config)# no npiv enable
DETAILED STEPS
| Command or Action | Purpose |
|---|
Verifying Fibre Channel Interfaces
Verifying SFP Transmitter Types
The SPF transmitter type can be displayed for a physical Fibre Channel interface (but not for a virtual Fibre Channel).
The small form-factor pluggable (SFP) hardware transmitters are identified by their acronyms when displayed in the show interface brief command. If the related SFP has a Cisco-assigned extended ID, then the show interface and show interface brief commands display the ID instead of the transmitter type. The show interface transceiver command and the show interface fc slot/port transceiver command display both values for Cisco supported SFPs.
Verifying Interface Information
The show interface command displays interface configurations. If no arguments are provided, this command displays the information for all the configured interfaces in the switch.
You can also specify arguments (a range of interfaces or multiple, specified interfaces) to display interface information. You can specify a range of interfaces by entering a command with the following example format:
interface fc2/1 - 4 , fc3/2 - 3
The following example shows how to display all interfaces:
switch# show interface
fc3/1 is up
...
fc3/3 is up
...
Ethernet1/3 is up
...
mgmt0 is up
...
vethernet1/1 is up
...
vfc 1 is up
...
The following example shows how to display multiple specified interfaces:
switch# show interface fc3/1 , fc3/3
fc3/1 is up
...
fc3/3 is up
...
The following example shows how to display a specific interface:
switch# show interface vfc 1
vfc 1 is up
...
The following example shows how to display interface descriptions:
switch# show interface description
-------------------------------------------------------------------------------
Interface Description
-------------------------------------------------------------------------------
fc3/1 test intest
Ethernet1/1 --
vfc 1 --
...
The following example shows how to display all interfaces in brief:
switch# show interface brief
The following example shows how to display interface counters:
switch# show interface counters
The following example shows how to display transceiver information for a specific interface:
switch# show interface fc3/1 transceiver
Note | The show interface transceiver command is only valid if the SFP is present. |
The show running-configuration command displays the entire running configuration with information for all interfaces. The interfaces have multiple entries in the configuration files to ensure that the interface configuration commands execute in the correct order when the switch reloads. If you display the running configuration for a specific interface, all the configuration commands for that interface are grouped together.
The following example shows the interface display when showing the running configuration for all interfaces:
switch# show running configuration
...
interface fc3/5
switchport speed 2000
...
interface fc3/5
switchport mode E
...
interface fc3/5
channel-group 11 force
no shutdown
The following example shows the interface display when showing the running configuration for a specific interface:
switch# show running configuration fc3/5
interface fc3/5
switchport speed 2000
switchport mode E
channel-group 11 force
no shutdown
Verifying BB_Credit Information
The following example shows how to display the BB_credit information for all Fibre Channel interfaces:
switch# show interface bbcredit
...
fc2/3 is trunking
Transmit B2B Credit is 255
Receive B2B Credit is 12
Receive B2B Credit performance buffers is 375
12 receive B2B credit remaining
255 transmit B2B credit remaining
Default Fibre Channel Interface Settings
The following table lists the default settings for native Fibre Channel interface parameters.
|
Parameters |
Default |
|---|---|
|
Interface mode |
Auto |
|
Interface speed |
Auto |
|
Administrative state |
Shutdown (unless changed during initial setup) |
|
Trunk mode |
On (unless changed during initial setup) |
|
Trunk-allowed VSANs |
1 to 4093 |
|
Interface VSAN |
Default VSAN (1) |
|
Beacon mode |
Off (disabled) |
|
EISL encapsulation |
Disabled |
|
Data field size |
2112 bytes |
The following table lists the default settings for virtual Fibre Channel interface parameters.
|
Parameters |
Default |
|---|---|
|
Interface mode |
Auto |
|
Interface speed |
n/a |
|
Administrative state |
Shutdown (unless changed during initial setup) |
|
Trunk mode |
n/a |
|
Trunk-allowed VSANs |
n/a |
|
Interface VSAN |
Default VSAN (1) |
|
EISL encapsulation |
n/a |
|
Data field size |
n/a |