Must 40/100G uplink ports on a 10G switch be connected to another switch?
I'm looking at a switch like this:
https://www.fs.com/products/29123.html
It has 48 10-GbE SFP+ ports and 6 40-GbE uplink ports. I would like to use some of these uplinks to cross-connect to another switch. In addition to that, however, I have a server with a 40-GbE capable NIC in it. Can this be connected directly to the 40-GbE port on the switch and "just work," or are these uplink ports special in that they must connect to uplink ports on another switch?
I know this used to be a thing for copper-based cabling before Auto-MDIX became commonplace, but it's not clear to me whether it's still an issue for modern SFP/QSFP-based connections.
switch uplinks 40g
asked yesterday
Jason RJason R
1453
add a comment |
I'm looking at a switch like this:
https://www.fs.com/products/29123.html
It has 48 10-GbE SFP+ ports and 6 40-GbE uplink ports. I would like to use some of these uplinks to cross-connect to another switch. In addition to that, however, I have a server with a 40-GbE capable NIC in it. Can this be connected directly to the 40-GbE port on the switch and "just work," or are these uplink ports special in that they must connect to uplink ports on another switch?
I know this used to be a thing for copper-based cabling before Auto-MDIX became commonplace, but it's not clear to me whether it's still an issue for modern SFP/QSFP-based connections.
switch uplinks 40g
asked yesterday
Jason RJason R
1453
2
Without knowing the server specs, one can't say for sure, but I would expect that the NIC was designed to connect to a switch (you could ask what else would it connect to?).
– Ron Trunk
yesterday
The server has this Mellanox NIC in it. I was making the assumption that there would be a standard answer to this type of question, as it's just a "vanilla" Ethernet NIC. The inherent question is whether the uplink ports on a switch like this are functionally any different from the others.
– Jason R
yesterday
add a comment |
I'm looking at a switch like this:
https://www.fs.com/products/29123.html
It has 48 10-GbE SFP+ ports and 6 40-GbE uplink ports. I would like to use some of these uplinks to cross-connect to another switch. In addition to that, however, I have a server with a 40-GbE capable NIC in it. Can this be connected directly to the 40-GbE port on the switch and "just work," or are these uplink ports special in that they must connect to uplink ports on another switch?
I know this used to be a thing for copper-based cabling before Auto-MDIX became commonplace, but it's not clear to me whether it's still an issue for modern SFP/QSFP-based connections.
switch uplinks 40g
asked yesterday
Jason RJason R
1453
I'm looking at a switch like this:
https://www.fs.com/products/29123.html
It has 48 10-GbE SFP+ ports and 6 40-GbE uplink ports. I would like to use some of these uplinks to cross-connect to another switch. In addition to that, however, I have a server with a 40-GbE capable NIC in it. Can this be connected directly to the 40-GbE port on the switch and "just work," or are these uplink ports special in that they must connect to uplink ports on another switch?
I know this used to be a thing for copper-based cabling before Auto-MDIX became commonplace, but it's not clear to me whether it's still an issue for modern SFP/QSFP-based connections.
switch uplinks 40g
switch uplinks 40g
asked yesterday
Jason RJason R
1453
asked yesterday
Jason RJason R
1453
asked yesterday
Jason RJason R
1453
asked yesterday
Jason RJason R
1453
asked yesterday
Jason RJason R
1453
1453
2
Without knowing the server specs, one can't say for sure, but I would expect that the NIC was designed to connect to a switch (you could ask what else would it connect to?).
– Ron Trunk
yesterday
The server has this Mellanox NIC in it. I was making the assumption that there would be a standard answer to this type of question, as it's just a "vanilla" Ethernet NIC. The inherent question is whether the uplink ports on a switch like this are functionally any different from the others.
– Jason R
yesterday
add a comment |
2
Without knowing the server specs, one can't say for sure, but I would expect that the NIC was designed to connect to a switch (you could ask what else would it connect to?).
– Ron Trunk
yesterday
The server has this Mellanox NIC in it. I was making the assumption that there would be a standard answer to this type of question, as it's just a "vanilla" Ethernet NIC. The inherent question is whether the uplink ports on a switch like this are functionally any different from the others.
– Jason R
yesterday
2
2
Without knowing the server specs, one can't say for sure, but I would expect that the NIC was designed to connect to a switch (you could ask what else would it connect to?).
– Ron Trunk
yesterday
Without knowing the server specs, one can't say for sure, but I would expect that the NIC was designed to connect to a switch (you could ask what else would it connect to?).
– Ron Trunk
yesterday
The server has this Mellanox NIC in it. I was making the assumption that there would be a standard answer to this type of question, as it's just a "vanilla" Ethernet NIC. The inherent question is whether the uplink ports on a switch like this are functionally any different from the others.
– Jason R
yesterday
The server has this Mellanox NIC in it. I was making the assumption that there would be a standard answer to this type of question, as it's just a "vanilla" Ethernet NIC. The inherent question is whether the uplink ports on a switch like this are functionally any different from the others.
– Jason R
yesterday
add a comment |
1 Answer
1
active
oldest
votes
That switch uses (Q)SFP+ ports which are essentially PHYless. You need to either use matching PHY type transceivers on both the switch and the host ports (e.g. 10GBASE-SR or 40GBASE-SR4) or direct-attach cables that are compatible with both sides.
The Mellanox NIC has QSFP28 ports that should support QSFP+ modules as well - check the documentation.
Note that most switches or NICs only support correctly branded transceivers - directly from the vendor or 3rd party compatible ones.
Whether the switch connects to a host or to another switch generally doesn't matter, assuming the port functions are configured appropriately.
MDI/MDI-X/Auto MDI-X are a special function of twisted-pair ports. The reason is that TP cables are straight-through historically and the receiver/transmitter crossover happens inside one of the link ports.
(Q)SFP(+) ports are all the same, the crossover happens within the cable (fiber or DAC).
answered yesterday
Zac67Zac67
30.5k21960
2
"Whether the switch connects to a host or to another switch generally doesn't matter" is the real answer, maybe should be on top?
– aaaaaa
yesterday
@aaaaaa Well, it may in some rare instances (twisted pair without Auto MDI-X), so I wanted to make sure the scenario is clear. I do actually disable Auto MDI-X on downlink and edge ports, and leave it enabled only on uplink ports.
– Zac67
10 hours ago
add a comment |
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1 Answer
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1 Answer
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active
oldest
votes
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votes
That switch uses (Q)SFP+ ports which are essentially PHYless. You need to either use matching PHY type transceivers on both the switch and the host ports (e.g. 10GBASE-SR or 40GBASE-SR4) or direct-attach cables that are compatible with both sides.
The Mellanox NIC has QSFP28 ports that should support QSFP+ modules as well - check the documentation.
Note that most switches or NICs only support correctly branded transceivers - directly from the vendor or 3rd party compatible ones.
Whether the switch connects to a host or to another switch generally doesn't matter, assuming the port functions are configured appropriately.
MDI/MDI-X/Auto MDI-X are a special function of twisted-pair ports. The reason is that TP cables are straight-through historically and the receiver/transmitter crossover happens inside one of the link ports.
(Q)SFP(+) ports are all the same, the crossover happens within the cable (fiber or DAC).
answered yesterday
Zac67Zac67
30.5k21960
2
"Whether the switch connects to a host or to another switch generally doesn't matter" is the real answer, maybe should be on top?
– aaaaaa
yesterday
@aaaaaa Well, it may in some rare instances (twisted pair without Auto MDI-X), so I wanted to make sure the scenario is clear. I do actually disable Auto MDI-X on downlink and edge ports, and leave it enabled only on uplink ports.
– Zac67
10 hours ago
add a comment |
That switch uses (Q)SFP+ ports which are essentially PHYless. You need to either use matching PHY type transceivers on both the switch and the host ports (e.g. 10GBASE-SR or 40GBASE-SR4) or direct-attach cables that are compatible with both sides.
The Mellanox NIC has QSFP28 ports that should support QSFP+ modules as well - check the documentation.
Note that most switches or NICs only support correctly branded transceivers - directly from the vendor or 3rd party compatible ones.
Whether the switch connects to a host or to another switch generally doesn't matter, assuming the port functions are configured appropriately.
MDI/MDI-X/Auto MDI-X are a special function of twisted-pair ports. The reason is that TP cables are straight-through historically and the receiver/transmitter crossover happens inside one of the link ports.
(Q)SFP(+) ports are all the same, the crossover happens within the cable (fiber or DAC).
answered yesterday
Zac67Zac67
30.5k21960
2
"Whether the switch connects to a host or to another switch generally doesn't matter" is the real answer, maybe should be on top?
– aaaaaa
yesterday
@aaaaaa Well, it may in some rare instances (twisted pair without Auto MDI-X), so I wanted to make sure the scenario is clear. I do actually disable Auto MDI-X on downlink and edge ports, and leave it enabled only on uplink ports.
– Zac67
10 hours ago
add a comment |
That switch uses (Q)SFP+ ports which are essentially PHYless. You need to either use matching PHY type transceivers on both the switch and the host ports (e.g. 10GBASE-SR or 40GBASE-SR4) or direct-attach cables that are compatible with both sides.
The Mellanox NIC has QSFP28 ports that should support QSFP+ modules as well - check the documentation.
Note that most switches or NICs only support correctly branded transceivers - directly from the vendor or 3rd party compatible ones.
Whether the switch connects to a host or to another switch generally doesn't matter, assuming the port functions are configured appropriately.
MDI/MDI-X/Auto MDI-X are a special function of twisted-pair ports. The reason is that TP cables are straight-through historically and the receiver/transmitter crossover happens inside one of the link ports.
(Q)SFP(+) ports are all the same, the crossover happens within the cable (fiber or DAC).
answered yesterday
Zac67Zac67
30.5k21960
That switch uses (Q)SFP+ ports which are essentially PHYless. You need to either use matching PHY type transceivers on both the switch and the host ports (e.g. 10GBASE-SR or 40GBASE-SR4) or direct-attach cables that are compatible with both sides.
The Mellanox NIC has QSFP28 ports that should support QSFP+ modules as well - check the documentation.
Note that most switches or NICs only support correctly branded transceivers - directly from the vendor or 3rd party compatible ones.
Whether the switch connects to a host or to another switch generally doesn't matter, assuming the port functions are configured appropriately.
MDI/MDI-X/Auto MDI-X are a special function of twisted-pair ports. The reason is that TP cables are straight-through historically and the receiver/transmitter crossover happens inside one of the link ports.
(Q)SFP(+) ports are all the same, the crossover happens within the cable (fiber or DAC).
answered yesterday
Zac67Zac67
30.5k21960
edited yesterday
answered yesterday
Zac67Zac67
30.5k21960
answered yesterday
Zac67Zac67
30.5k21960
answered yesterday
Zac67Zac67
30.5k21960
30.5k21960
2
"Whether the switch connects to a host or to another switch generally doesn't matter" is the real answer, maybe should be on top?
– aaaaaa
yesterday
@aaaaaa Well, it may in some rare instances (twisted pair without Auto MDI-X), so I wanted to make sure the scenario is clear. I do actually disable Auto MDI-X on downlink and edge ports, and leave it enabled only on uplink ports.
– Zac67
10 hours ago
add a comment |
2
"Whether the switch connects to a host or to another switch generally doesn't matter" is the real answer, maybe should be on top?
– aaaaaa
yesterday
@aaaaaa Well, it may in some rare instances (twisted pair without Auto MDI-X), so I wanted to make sure the scenario is clear. I do actually disable Auto MDI-X on downlink and edge ports, and leave it enabled only on uplink ports.
– Zac67
10 hours ago
2
2
"Whether the switch connects to a host or to another switch generally doesn't matter" is the real answer, maybe should be on top?
– aaaaaa
yesterday
"Whether the switch connects to a host or to another switch generally doesn't matter" is the real answer, maybe should be on top?
– aaaaaa
yesterday
@aaaaaa Well, it may in some rare instances (twisted pair without Auto MDI-X), so I wanted to make sure the scenario is clear. I do actually disable Auto MDI-X on downlink and edge ports, and leave it enabled only on uplink ports.
– Zac67
10 hours ago
@aaaaaa Well, it may in some rare instances (twisted pair without Auto MDI-X), so I wanted to make sure the scenario is clear. I do actually disable Auto MDI-X on downlink and edge ports, and leave it enabled only on uplink ports.
– Zac67
10 hours ago
add a comment |
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2
Without knowing the server specs, one can't say for sure, but I would expect that the NIC was designed to connect to a switch (you could ask what else would it connect to?).
– Ron Trunk
yesterday
The server has this Mellanox NIC in it. I was making the assumption that there would be a standard answer to this type of question, as it's just a "vanilla" Ethernet NIC. The inherent question is whether the uplink ports on a switch like this are functionally any different from the others.
– Jason R
yesterday