MAC address assignment of ftServer® V Series and Continuum® network interface adapters
 

Noah Davids
Stratus Support Engineer
Stratus Technologies
mailto:noah.davids@stratus.com

In our last eNewsletter, we discussed how MAC addresses are assigned to network interface adapters runninng on a Stratus® ftServer® system. This article will explain how the addresses are assigned to network interface adapters running on ftServer® V Series systems and Continuum® systems using either the STCP or TCP_OS TCP stacks.

ftServer V Series system

The ftServer V Series system has a number of different network interface adapters. However, there are two broad classes of adapters — embedded adapters and PCI adapters. The embedded adapters are housed in the core IO chassis. The PCI adapters are PCI cards that can be inserted into any of the PCI slots in either a core or expansion chassis.

MAC addresses on the PCI adapters

Each adapter has an address assigned by the factory when it is made. The first three bytes are assigned to the manufacturer by the Institute of Electrical and Electronics Engineers (IEEE), and are called the organizationally unique identifier (OUI). You can search for a specific OUI at http://standards.ieee.org/regauth/oui/index.shtml. The manufacturer assigns the last three bytes. Typically, ports on the same adapter will have sequential values but there is no predictability when going from one adapter to another.

In figure 1, you can see the MAC address using the analyze_system request dump_genet. Matching on the word MAC significantly reduces the output; the address is the "EEPROM MAC address" value.

  as:  match MAC; dump_genet #enet.m15.12.1.0  
     EEPROM MAC address                       = 000423B2238A  
     MacType                                  = MAC_82546

Figure 1 - Checking the EEPROM MAC address assignments of PCI adapters

All the PCI cards supported on the V Series system are manufactured by Intel and will have an Intel® OUI, but since Intel has many OUIs, it is hard to tell which one will be on your card.

Note: when using sdlmux, the EEPROM MAC address is not used. Refer to the section "Effects of sdlmux on MAC address" later in this article to see how the address assignment is changed.

MAC addresses on the embedded adapters

The V Series system has one embedded 10/100/1000 adapter in each core IO. The MAC addresses of these adapters are based on data in the SROM chip in each system. The adapter in core IO 10 is given the address found in the SROM, the adapter in core IO 11 is given in that address SROM + 2.

You will see this with dump_genet in figure 2. The 00-04-FC OUI of these adapters belongs to Stratus.

  as:  match MAC; dump_genet #enet.m15.10.3
     EEPROM MAC address                       = 0004FC01292B  
     MacType                                  = MAC_CORDOVA
  as:  match MAC; dump_genet #enet.m15.11.3
     EEPROM MAC address                       = 0004FC01292D  
     MacType                                  = MAC_CORDOVA

Figure 2 - Checking the EEPROM MAC address assignments of embedded adapters

Note: when using sdlmux, the EEPROM address is not used. Refer to the section "Effects of sdlmux on MAC address" later in this article to see how the address assignment is changed.

Stratus Continuum system

Continuum systems support three types of Ethernet adapters.

IOA cards

The K104 card is an IOA adapter using the dlmux and GDL drivers. The dlmux driver is used to duplex two K104 cards, supporting a fault-tolerant Ethernet connection, but is required even if no duplex pairs are defined. Like sdlmux, when using dlmux, the factory assigned MAC address is not used. However, there is no way to determine what the factory assigned MAC address is. See "Effects of dlmux on MAC address" later in this article.

Big boards

The K450 and K460 cards are "big boards" that house both an Ethernet adapter and SCSI ports. Both cards use the dlmux and BDL drivers. Like the K104 card, the dlmux driver is needed even if the card does not have a partner. Also like the K104, there is no way to see the factory assigned MAC address. See "Effects of dlmux on MAC address" later in this article.

PCM cards

The U713 and U714 cards are PCM adapters housed in a K470 or K480 big board card. The U713 uses the renet driver, while the U714 uses the genet driver. These cards do not require the dlmux driver, but they can be duplexed with sdlmux.

You can display their factory assigned MAC address with the dump_renet (figure 3) or dump_genet (figure 4) requests in analyze_system.

  as:  match MAC; dump_renet #stcp_u713.m14.6.2
     EEPROM MAC address                       = 0000BC126553

Figure 3 - Checking the EEPROM MAC address assignment of a U713 adapter 

  as:  match MAC; dump_genet #stcp_u714.m14.6.3
     EEPROM MAC address                       = 0010321003D6

Figure 4 - Checking the EEPROM MAC address assignment of a U714 adapter

The U713 cards have the OUI 00:00:BC assigned to ALLEN-BRADLEY while the U714 has 00:10:32 assigned to ALTA TECHNOLOGY.

Note: when using sdlmux, the EEPROM address is not used. Refer to the following section "Effects of sdlmux on MAC address" to see how the address assignment is changed.

Effects of sdlmux on the MAC address

ftServer V Series system

When two adapters are duplexed using sdlmux, one adapter, designated the active adapter, transmits all data frames while the other adapter acts as a standby. The active adapter is assigned the MAC address 00:00:A8:4v:wx:yz while the standby adapter is assigned the address 00:00:A8:6v:wx:yz. V is the sdlmux entry number. The values wx:yz are derived from the system serial number. The EEPROM address of the adapter is not used. Note that the two addresses differ only in bit 27. If you are not looking for it, is easy to think that both adapters have the same MAC address. You can see this with dump_genet, matching on "node" (figure 5); enet.m15.10.3 is the active adapter. 

  as:  match node; dump_genet #enet.m15.10.3
   current node address                     = 0000A8403B6E    
  as:  match node; dump_genet #enet.m15.11.3
   current node address                     = 0000A8603B6E

Figure 5 - V Series system sdlmux assigned addresses

You can also see the MAC address of the active adapter using the netstat command. With netstat you use the name of the IP interface, not the adapter (figure 6). 

  netstat -interface #sdlmuxA.m15.10.3

  Ethernet adapters are grouped
  Number of failovers = 6

  Active Device Statistics:


  MAC Type   : CSMA/CD
  MAC Address: 00:00:a8:40:3b:6e                              
  Device Name: #sdlmuxA.m15.10.3
  Line Speed : 1000 mb/s
  . . .

Figure 6 - Using netstat to see the active adapter's MAC address

Both adapters transmit test frames to the other adapter to confirm that the adapter and the network are working. So both MAC addresses will show up in a switch's address cache.

When the system diagnoses a problem with the active adapter, the standby adapter will take over. When that happens, the standby adapter's MAC address is changed to become the active adapter's MAC address, and the old active adapter, now the standby, changes its MAC address so it now has the standby adapter's MAC address. Switches have to be configured to allow both MAC addresses to appear on either port.

Stratus recommends that all STCP devices be configured to use sdlmux — even if they do not have a partner. The sdlmux driver provides several useful functions. From the standpoint of MAC addresses, it keeps the MAC address of the adapters constant even if the adapter is changed. The single adapter is assigned the active MAC address.

Continuum system

With the exception of address assignments, there is no difference in the behavior of sdlmux running on the V Series system or the Continuum system.

On a Continuum system, the active U713 or U714 adapter is assigned the MAC address 00:00:A8:Cv:wx:yz while the standby adapter is assigned the address 00:00:A8:Ev:wx:yz (figure 7); stcp_u713.m14.6.1 is the active adapter.

  as:  match node; dump_renet #stcp_u713.m14.6.1
     current node address                     = 0000A8C086A1  
  as:  match node; dump_renet #stcp_u713.m14.7.1
     current node address                     = 0000A8E086A1

Figure 7 - Continuum sdlmux assigned addresses

Like the V Series system, the netstat command can be used to display the MAC address of the active adapter of an IP interface.

Effects of dlmux on MAC address

ftServer V Series system

Dlmux does not run on the V Series system.

Continuum system

On a Continuum system, dlmux is used for the K104, K450 and K460 cards. It is required even if the adapter is not partnered with another adapter. It behaves almost exactly like sdlmux. One adapter is the active adapter while the other, if there is another, is the standby. The active adapter is assigned the MAC address: 00:00A8:8v:wx:yz, the standby is assigned 00:00:A8:Av:wx:yz. The V is the dlmux entry number. TCP_OS devices start at 0 and work up, and STCP devices start at F and work down. The values wx:yz are derived from the system serial number. Since dlmux is always in use, there is no way to observe the factory assigned MAC address of these adapters.

You can use the dump_gdl_entry analyze_system request to look directly at the address assignments of K104 cards (figure 8). The request does not display the device name. Instead, it displays a device_id which is the device location. The first byte corresponds to the slot number of the IOP big board that controls the IOA chassis housing adapter. The next byte is the slot number of the adapter in the IOA chassis. In figure 8, the first card is in slot 13 (D) and is the ACTIVE member of a TCP_OS pair. The second card is in slot 12 (C) and is the ACTIVE member of an STCP pair. Since these are the only devices displayed, we can conclude that neither device is duplexed. 

  as:  match device_id -or mac_addr; dump_gdl_entry -all 
  device_id                    : 0A0DFFFF
  mac_addr                     : 00:00:a8:80:81:ec
  device_id                    : 0A0CFFFF
  mac_addr                     : 00:00:a8:8e:81:ec

Figure 8 - dlmux assigned K104 addresses

You can use the dump_bdl_entry analyze_system request to look directly at the address assignments of K450 and K460s (figure 9). Like dump_gdl_entry, the request does not display the device name. It displays the device_id instead. The first byte corresponds to the slot number that the card is in. The next byte is always 5. In figure 9, the first card is in slot 4, and is the standby member of an STCP pair. The second card is in slot 5, and is the ACTIVE member of an STCP pair. Since the "V" nibble is the same for both adapters we know that they are partners. 

  as:  match device_id -or mac_addr:; dump_bdl_entry -all  
       bio_device_id           : 0405FFFF
       mac_addr:               : 0000A8AF81EC
       bio_device_id           : 0505FFFF
       mac_addr:               : 0000A88F81EC

Figure 9 - dlmux assigned K450/K460 addresses

You can see the dlmux assigned address of the active adapter of an IP interface with the netstat command.

Like sdlmux devices, it is important that the switch ports that these adapters are connected to accept frames with either the active or standby MAC address in the source field.

Determining the active adapter

The dlmux_admin command with either the get_status (figure 10 ) or sdlmux_status (figure 11) arguments can be used to determine which adapter is the active adapter. The dlmux_admin command takes, as its first argument, the name of the IP interface, not the adapter name, although for a K104, K450 or K460 the interface name is also an adapter name. The interface name is the name used with the ifconfig command. The active adapter has the keyword ACTIVE in its state. 

  dlmux_admin k460.m2.4 get_status
  Device Name:         %phx_cac#k460.m2.4            
  Adapter State:       UP
  Partner:             %phx_cac#k460.m2.5  
  Partner State:       ACTIVE   UP

Figure 10 - dlmux_admin showing active/standby dlmux device 

  dlmux_admin #sdlmux30.16 sdlmux_status  
  Group Name:          #sdlmux30.16  
  Device Name:         %es#renet.30.6.1              
  Adapter State:       ACTIVE   UP  
  Partner:             %es#renet.30.7.1  
  Partner State:       UP

Figure 11 - sdlmux_admin showing active/standby sdlmux device

Summary

  Active Standby
V Series system simplexed adapter Some INTEL OUI  
V Series system duplexed (sdlmux) adapter 00:00:A8:4v:wx:yz 00:00:A8:6v:wx:yz
Continuum simplexed PCM U713 adapter 00:00:BC  
Continuum simplexed PCM U714 adapter 00:10:32  
Continuum duplexed PCM (sdlmux) adapter 00:00:A8:Cv:wx:yz 00:00:A8:Ev:wx:yz
Continuum simplexed K104. K450, K460 (dlmux) adapter 00:00A8:8v:wx:yz  
Continuum duplexed K104, K450, K460 (dlmux) adapter 00:00A8:8v:wx:yz 00:00A8:Av:wx:yz

Table 1 - Summary of MAC address assignments

The views expressed in this article are entirely those of the author(s), and should not be attributed in any manner to Stratus, or its affiliated entities. The author(s) are solely responsible for the information, material and content of this articles.

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