How do people deal with situation where you need <=48 SFP/SFP+ ports, but
you occasionally need one or two cu 10/100 ports?
For some reason it's becoming quite rare for SFP port to natively support
10M and 100M rates.
Technically obviously solution to me would be subrate SFP, which presents
itself as 1GE to host, offering 100M or 10M to client. This would obviously
break QoS at the host as host would still think it's 1GE and SFP itself
would need to drop+buffer. But for my applications it would be fine, the
10M or 100M ports are typical some MGMT access interfaces.
I can't imagine such SFP being complex or expensive, considering we have E1
over IP in a SFP, which includes control-plane and forwarding-plane inside
SFP form-factor
Is this demand peculiar? Could I source such SFP somewhere by showing there
is demand?
Putting 2 port switches or fibre converters with external PSU just to
support few ports seem dirty.
How do people deal with situation where you need <=48 SFP/SFP+ ports, but
you occasionally need one or two cu 10/100 ports?
arista 7050s support 100 Mb/s on their copper sfp I have leveraged that,
if you can break out the 40Gb/s ports you have as many as 64 ports of
10Gb/s. there are other switches that I've seen do this but they're not
common.
My problem is mostly around PDU/CDU management, in racks that otherwise
would be 10Gb/s only and in general I've addressed it with dedicated
switches that support many of these devices rather than just two.
I got quite a bit of replies from sellers selling me cuSFP, insisting they
work.
So I'd like to clear up on this. For 10/100 to work on SFP slot, the PHY in
the host needs to be multirate. Exception is SGMII which supposedly
supports magic mode where SFP can ask it to send same bit 10 times, then
SFP can discard 9/10 bits, to remain very dumb yet deliver 100M client on
1GE host.
RGMII does not support this trick and this trick does not bring you down to
10M. One box that we have right now, which can't do any of this is ME-4924.
There is absolutely no reason that you couldn't deliver 'media converter'
or '2 port switch' in a SFP casing, to get that 1 10/100 port in every
4500-X or EX4550 port you need to cater some legacy. If my desire is odd (2
people have expressed off list they want same) this won't be built. But if
this is somewhat common demand and missing product, we can certainly get
such SFP built.
Obviously this SFP would cost bit more than normal cuSFP, as it needs to do
rudimentary buffering, packet dropping and it needs to have frame parser.
I got quite a bit of replies from sellers selling me cuSFP, insisting they
work.
So I'd like to clear up on this. For 10/100 to work on SFP slot, the PHY in
the host needs to be multirate. Exception is SGMII which supposedly
supports magic mode where SFP can ask it to send same bit 10 times, then
SFP can discard 9/10 bits, to remain very dumb yet deliver 100M client on
1GE host.
RGMII does not support this trick and this trick does not bring you down to
10M. One box that we have right now, which can't do any of this is ME-4924.
There is absolutely no reason that you couldn't deliver 'media converter'
or '2 port switch' in a SFP casing, to get that 1 10/100 port in every
4500-X or EX4550 port you need to cater some legacy. If my desire is odd (2
people have expressed off list they want same) this won't be built. But if
this is somewhat common demand and missing product, we can certainly get
such SFP built.
Obviously this SFP would cost bit more than normal cuSFP, as it needs to do
rudimentary buffering, packet dropping and it needs to have frame parser.
Considering that Dell and HP at least are shipping brand new hardware with IPMI/BMC/iLO/whatever management ports that can only speak 100mbit when every other Ethernet interface in the box at least gigabit, having a useful way to talk to that port without having to keep separate switching hardware around would be nice. I'm not holding my breath, but you know, along with a pony, this would be nice.
> From: Saku Ytti [mailto:saku@ytti.fi]
Considering that Dell and HP at least are shipping brand new hardware with
IPMI/BMC/iLO/whatever management ports that can only speak 100mbit when
every other Ethernet interface in the box at least gigabit, having a useful
way to talk to that port without having to keep separate switching hardware
around would be nice. I'm not holding my breath, but you know, along with
a pony, this would be nice.
Eh? That may have been the case a few years ago, but HP ILO4 and
iDRAC7 specifically list 10/100/1000 even when using in dedicated port
mode.
And even in prior versions, you could have the port linking up at 1Gbps,
by operating the management in Shared port mode (Sharing the management
with the server's Eth0).
I expect over time: support for linking up at 10/100 will get rarer and
much more expensive.
The niche status a 10/100 media converter as an SFP would have if produced
is likely to mean it would retail at $2000+ per port device.
It probably just makes more sense to go find an old obsolete top of rack
switch, like a Cat3750 to get the small fraction of legacy copper ports
required for out of band network and server management, which: by the
way, should be part of a separate switching infrastructure anyways, to
increase the chance it stays operational and useful for troubleshooting, in
the event the production network experiences outage or has other issues
requiring diagnosis.
Unless I missed something, iLO is always on when the machine has power; as such, WOL shouldn't be coming into play on reasonably modern HP servers. (That said, the power draw is likely still the reason, although I can't readily confirm Charles' observation on my only rackmount Gen8.)