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 sfp uplinks 40g
edited Mar 8 at 8:34
Zac67
32.7k22164
asked Mar 6 at 15:08
Jason RJason R
1503
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 sfp uplinks 40g
edited Mar 8 at 8:34
Zac67
32.7k22164
asked Mar 6 at 15:08
Jason RJason R
1503
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
Mar 6 at 15:15
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
Mar 6 at 15:18
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 sfp uplinks 40g
edited Mar 8 at 8:34
Zac67
32.7k22164
asked Mar 6 at 15:08
Jason RJason R
1503
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 sfp uplinks 40g
switch sfp uplinks 40g
edited Mar 8 at 8:34
Zac67
32.7k22164
asked Mar 6 at 15:08
Jason RJason R
1503
edited Mar 8 at 8:34
Zac67
32.7k22164
asked Mar 6 at 15:08
Jason RJason R
1503
edited Mar 8 at 8:34
Zac67
32.7k22164
edited Mar 8 at 8:34
Zac67
32.7k22164
edited Mar 8 at 8:34
Zac67
32.7k22164
32.7k22164
asked Mar 6 at 15:08
Jason RJason R
1503
asked Mar 6 at 15:08
Jason RJason R
1503
asked Mar 6 at 15:08
Jason RJason R
1503
1503
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
Mar 6 at 15:15
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
Mar 6 at 15:18
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
Mar 6 at 15:15
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
Mar 6 at 15:18
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
Mar 6 at 15:15
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
Mar 6 at 15:15
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
Mar 6 at 15:18
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
Mar 6 at 15:18
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 Mar 6 at 15:54
Zac67Zac67
32.7k22164
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
Mar 6 at 23:49
@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
Mar 7 at 21:04
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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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 Mar 6 at 15:54
Zac67Zac67
32.7k22164
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
Mar 6 at 23:49
@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
Mar 7 at 21:04
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 Mar 6 at 15:54
Zac67Zac67
32.7k22164
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
Mar 6 at 23:49
@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
Mar 7 at 21:04
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 Mar 6 at 15:54
Zac67Zac67
32.7k22164
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 Mar 6 at 15:54
Zac67Zac67
32.7k22164
edited Mar 6 at 16:07
answered Mar 6 at 15:54
Zac67Zac67
32.7k22164
answered Mar 6 at 15:54
Zac67Zac67
32.7k22164
answered Mar 6 at 15:54
Zac67Zac67
32.7k22164
32.7k22164
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
Mar 6 at 23:49
@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
Mar 7 at 21:04
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
Mar 6 at 23:49
@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
Mar 7 at 21:04
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
Mar 6 at 23:49
"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
Mar 6 at 23:49
@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
Mar 7 at 21:04
@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
Mar 7 at 21:04
add a comment |
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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
Mar 6 at 15:15
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
Mar 6 at 15:18