20 - this is a Node (WWNN)
21 - this is the WWPN of Port 1
22 - this is the WWPN of Port 2
FC_ID: 24 Bit Address Space
- N_Port ID is assigned by the fabric when a world wide name registers with it.
- For physical port, N_Port sends FLOGI (with WWPN of physical port) to address 0xFFFFFE to obtain a valid address (N_Port ID).
- For virtual port, N_Port sends FDISC (with WWPN of virtual port) to address 0xFFFFFE to obtain an additional address (Virtual N_Port ID)
Fabric: term to describe a generic switching environment, it can consist of one or more interconnected switches (domains).
One Fibre Channel Switch = One Fabric Domain.
Maximum Domains = 239 in a single Fabric based on 24-bit addressing.
Principal Switch: Determine precedence between FC Swithced without adding a separate external. Fabric management software. it facilitates the initialization of the Fabric, and acts as controller of domains.
Maximum Domains = 239 in a single Fabric based on 24-bit addressing.
Principal Switch: Determine precedence between FC Swithced without adding a separate external. Fabric management software. it facilitates the initialization of the Fabric, and acts as controller of domains.
Switch Ports:
E_port – expansion port, connects 2 FC switches together to make a Fabric.
F_port – Fabric port where N_port attaches.
FL_port – Fabric loop port where NL_Port attaches.
E_port – expansion port, connects 2 FC switches together to make a Fabric.
F_port – Fabric port where N_port attaches.
FL_port – Fabric loop port where NL_Port attaches.
Device Ports:
N_port – port designator for direct fabric attached devices.
NL_port – device that is attached to the loop (seldom used, support for old FC stuff).
N_port – port designator for direct fabric attached devices.
NL_port – device that is attached to the loop (seldom used, support for old FC stuff).
FC_ID: 24 Bit Address Space: Dynamically assigned during login.
| Domain ID | Area ID | Node ID |
Domain ID = upper 8 bits, identifies the FC Switch
Area ID = middle 8 bits, identifies port number
Node ID = lower 8 bits, N_Port address
| Domain ID | Area ID | Node ID |
Domain ID = upper 8 bits, identifies the FC Switch
Area ID = middle 8 bits, identifies port number
Node ID = lower 8 bits, N_Port address
Unique Identification:
-Fixed 64bit value assigned by manufacturer.
-Used in mapping to upper layer protocols.
WWPN: uniquely identify a port (Port_Name).
WWNN: uniquely identify a node (Node_Name).
-Fixed 64bit value assigned by manufacturer.
-Used in mapping to upper layer protocols.
WWPN: uniquely identify a port (Port_Name).
WWNN: uniquely identify a node (Node_Name).
FC defines two types of login procedures:
Fabric Login (flogi) – After link established, N_Port sends flogi frames to the fabric and receive responses back.
Fabric Login (flogi) – After link established, N_Port sends flogi frames to the fabric and receive responses back.
N_Port Login (plogi) – Enable a N_port to communicate with another N_port. Once logged in, it will stay indefinitely.
FC transmits data in frames, defines variable length:
36 bytes of overhead
SOF – 4 bytes
Header – 24 bytes
CRC – 4 bytes
EOF – 4 bytes
Up to 2112 bytes of payload
Optional Header – up to 64 bytes
Data – up to 2048 bytes
36 bytes of overhead
SOF – 4 bytes
Header – 24 bytes
CRC – 4 bytes
EOF – 4 bytes
Up to 2112 bytes of payload
Optional Header – up to 64 bytes
Data – up to 2048 bytes
FC Layers:
FC-4: Upper layer protocola interface – SCSI, IP, and so on roughly as transport layer in the OSI model.
FC-3: common Services
FC-2: Data delivery – Framing Protocol and Flow Control. Similer to layer 2 of OSI.
FC-1: Encoding – 8b/10b (1,2,4,9 Gb/s) and 64b/66b (10 Gb/s). Link Controls
FC-0: Physical Interface – Media Connectors and Cables.
FC-4: Upper layer protocola interface – SCSI, IP, and so on roughly as transport layer in the OSI model.
FC-3: common Services
FC-2: Data delivery – Framing Protocol and Flow Control. Similer to layer 2 of OSI.
FC-1: Encoding – 8b/10b (1,2,4,9 Gb/s) and 64b/66b (10 Gb/s). Link Controls
FC-0: Physical Interface – Media Connectors and Cables.
FC starndards site: http://www.t11.org
FC-FS: Fibre Channel Framing and Signaling Interface
FC-LS: Fibre Channel Link Service
FC-GS: Fibre Channel General Services
FCP: Fibre Channel Protocol for SCSI
FC-FS: Fibre Channel Framing and Signaling Interface
FC-LS: Fibre Channel Link Service
FC-GS: Fibre Channel General Services
FCP: Fibre Channel Protocol for SCSI
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- Zones are partitions, similar to VLANs. Ports or WWNs can live in multiple zones at the same time.
- Soft zones enforce partitioning based on WWN, and they're difficult to manage if fiber moves to a new port.
- Hard zones are port-based: you can keep track of what node is attached where. Hybrid zones exist on some switches, for the paranoid: "WWN C must live on this port."
Soft Zones
Soft zoning means that the switch will place WWNs of devices in a zone, and it doesn't matter what port they're connected to. If WWN Q, for example, lives in the same soft zone as WWN Z, they will be able to talk to each other. Likewise, if Z and A are in a separate zone, they can see each other, but A cannot see Q. This is the complexity part; a feature that isn't widespread in Ethernet switches.
The benefit to using soft zones is that you can connect to any port on a switch, and know that you'll have access to the other nodes you're supposed to see.
Hard Zones
Hard zones are more like VLANs in the Ethernet world. You place the port into a zone, and anything connecting to that port is in the zone, or zones, which are configured for that port. Sure, it is less secure in the event of a physical attack where someone is able to move fiber connections.
really nice, thank you!
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