This topic covers the fundamentals of Ethernet interface, such as supported hardware, ethernet protocol standards, flow control and so on.
Cisco 8000 modular line cards
The Cisco 8800 Series Routers support these line cards:
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36-port QSFP56-DD 400 GbE Line Card - This line card provides 14.4 Tbps via 36 QSFP56-DD ports. It also supports 100G, 2x100G, and 400G modules. If 36 of 2x100G modules are used, the line card can have 72 HundredGigE interfaces.
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48-port QSFP28 100 GbE Line Card - This line card provides 4.8 Tbps with MACsec support on all ports. It also supports QSFP+ optics for 40G compatibility.
The 8800 Series line cards utilize multiple #ChipName forwarding ASICs to achieve high performance and bandwidth with line rate forwarding.
Gigabit Ethernet protocol standards
The Gigabit Ethernet interfaces on Cisco 8000 Series Routers support these IEEE Ethernet protocol standards.
| Standard |
Description |
|---|---|
| IEEE 802.3 physical Ethernet infrastructure |
Defines the physical layer and MAC sublayer of the data link layer of wired Ethernet. IEEE 802.3 uses Carrier Sense Multiple Access with Collision Detection (CSMA/CD) access at various speeds over various physical media. The IEEE 802.3 standard covers 10 Mbps Ethernet. Extensions to the IEEE 802.3 standard specify implementations for 40-Gigabit Ethernet and 100-Gigabit Ethernet. |
| IEEE 802.3ae 10-Gbps Ethernet |
Under the International Standards Organization's Open Systems Interconnection (OSI) model, Ethernet is fundamentally a Layer 2 protocol. 10-Gigabit Ethernet uses the IEEE 802.3 Ethernet MAC protocol, the IEEE 802.3 Ethernet frame format, and the minimum and maximum IEEE 802.3 frame size. 10-Gbps Ethernet conforms to the IEEE 802.3ae protocol standards. Just as 1000BASE-X and 1000BASE-T (Gigabit Ethernet) remained true to the Ethernet model, 10-Gigabit Ethernet continues the natural evolution of Ethernet in speed and distance. Because it is a full-duplex only and fiber-only technology, it does not need the carrier-sensing multiple-access with the CSMA/CD protocol that defines slower, half-duplex Ethernet technologies. In every other respect, 10-Gigabit Ethernet remains true to the original Ethernet model. |
| IEEE 802.3ba 100-Gbps Ethernet |
IEEE 802.3ba is supported on the Cisco 1-Port 100-Gigabit Ethernet PLIM. |
MAC address
A MAC address is a unique 6-byte address that
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identifies the interface at Layer 2 and
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describes the platform limit on distinct MAC most significant bytes (MSBs) across Layer 3 interfaces on Cisco 8000 Series Routers.
MAC address usage on Layer 3 interfaces
To ensure system stability on Cisco 8000 Series routers running IOS XR, restrict the total number of distinct 4-byte MAC (MSBs) to no more than 15 across all Layer 3 interfaces, including physical interfaces, bundle interfaces, BVI interfaces, and PWHE interfaces.
If you exceed this limit, creation of additional Layer 3 interfaces, such as Bundle-Ether interfaces may fail during hardware programming. The interface may appear to be created and then be immediately removed, and you may see No space left on device errors in system logs from the forwarding plane. Once the platform resource limit is reached, you cannot program more interfaces in hardware until resources are freed.
Adhering to this requirement prevents resource exhaustion and ensures reliable operation when configuring multiple Layer 3 interfaces.
Default configuration values for 100-Gigabit Ethernet
This table describes the default interface configuration parameters that are present when an interface is enabled on a 36-port Line Card or a 48-port Line Card.
You must use the shutdown command to bring an interface administratively down. The interface default is no shutdown . When a line card is first inserted into the router, if there is no established preconfiguration for it, the configuration manager adds a shutdown item to its configuration. This shutdown can be removed only be entering the no shutdown command.
Parameter |
Configuration File Entry |
Default Value |
|---|---|---|
Flow control |
flow-control |
egress off ingress off |
MTU |
mtu |
|
MAC address |
mac address |
Hardware burned-in address (BIA) |
Flow control on Ethernet interfaces
The 10-Gigabit Ethernet flow control is a mechanism that:
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sends flow control pause frames periodically
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differs from standard full and half-duplex flow control, and
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manages traffic flow on 10-Gigabit Ethernet interfaces.
The router manages traffic flow through these configurations:
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You can activate or deactivate flow control for only ingress traffic.
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The router automatically implements flow control for egress traffic.
Configure physical Ethernet interfaces
Before you begin
Check the current software version and the configured interface, and check the status of each interface port by using these commands:-
show version – displays the current software version, and can also be used to confirm that the router recognizes the line card.
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show interfaces [ TenGigE FortyGigE HundredGigE FourHundredGigE] interface-path-id – displays the configured interface and checks the status of each interface port.
Use this procedure to create a basic Ethernet interface configuration.
Procedure
| 1. | Enter the global configuration mode. Example: |
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| 2. | Enter the interface configuration mode and specify the Ethernet interface name and notation rack/slot/module/portshow interfaces [ TenGigE FortyGigE HundredGigE FourHundredGigE] interface-path-id Example:Possible interface types for this procedure are:
The examples of interface-path-id ranges are:
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| 3. | Assign an IP address and subnet mask to the interface by using ipv4 address ip-address mask command. Example:
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| 4. | (Optional) Enable the sending and processing of flow control pause frames by using theflow-control {bidirectional| egress | ingress} command. Example:
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| 5. | Use mtu bytes to set the MTU value for the interface. Example:
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| 6. | Use no shutdown to remove the shutdown configuration, which forces an interface administratively down. Example: |
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| 7. | Save configuration changes. end or commit Example:or
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