Posible to connect VLAN switch through dumb switch?
up vote
6
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Is it possible to connect a VLAN switch into a dumb switch ?
The router will know how to reach network connected by a VLAN through the dumb switch please ?
No edge effect ?
By example, a schema of the project :
Thanks !
switch vlan
asked Nov 12 at 15:49
Puma
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add a comment |
up vote
6
down vote
favorite
Is it possible to connect a VLAN switch into a dumb switch ?
The router will know how to reach network connected by a VLAN through the dumb switch please ?
No edge effect ?
By example, a schema of the project :
Thanks !
switch vlan
asked Nov 12 at 15:49
Puma
312
New contributor
Puma is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Normally it would not be a problem.
– Cown
Nov 12 at 15:53
1
Possible? Yes. Recommended? No. A "hub" that isn't vlan aware could do anything with tagged traffic. The biggest problem: the frames are now 4 bytes bigger, which can cause them to be dropped as oversized. (1518 vs 1514) In the absolute worst case, your "hub" crashes when presented tagged traffic. (a Cisco 2900XL, for example)
– Ricky Beam
Nov 12 at 19:05
Can you reconfigure things so the unmanaged switch is not in that path? Would be a better network design if so.
– Criggie
Nov 12 at 19:43
add a comment |
up vote
6
down vote
favorite
up vote
6
down vote
favorite
Is it possible to connect a VLAN switch into a dumb switch ?
The router will know how to reach network connected by a VLAN through the dumb switch please ?
No edge effect ?
By example, a schema of the project :
Thanks !
switch vlan
asked Nov 12 at 15:49
Puma
312
New contributor
Puma is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
Is it possible to connect a VLAN switch into a dumb switch ?
The router will know how to reach network connected by a VLAN through the dumb switch please ?
No edge effect ?
By example, a schema of the project :
Thanks !
switch vlan
switch vlan
asked Nov 12 at 15:49
Puma
312
New contributor
Puma is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked Nov 12 at 15:49
Puma
312
New contributor
Puma is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited Nov 12 at 16:12
asked Nov 12 at 15:49
Puma
312
New contributor
Puma is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked Nov 12 at 15:49
Puma
312
asked Nov 12 at 15:49
Puma
312
312
New contributor
Puma is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
Puma is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
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Check out our Code of Conduct.
Normally it would not be a problem.
– Cown
Nov 12 at 15:53
1
Possible? Yes. Recommended? No. A "hub" that isn't vlan aware could do anything with tagged traffic. The biggest problem: the frames are now 4 bytes bigger, which can cause them to be dropped as oversized. (1518 vs 1514) In the absolute worst case, your "hub" crashes when presented tagged traffic. (a Cisco 2900XL, for example)
– Ricky Beam
Nov 12 at 19:05
Can you reconfigure things so the unmanaged switch is not in that path? Would be a better network design if so.
– Criggie
Nov 12 at 19:43
add a comment |
Normally it would not be a problem.
– Cown
Nov 12 at 15:53
1
Possible? Yes. Recommended? No. A "hub" that isn't vlan aware could do anything with tagged traffic. The biggest problem: the frames are now 4 bytes bigger, which can cause them to be dropped as oversized. (1518 vs 1514) In the absolute worst case, your "hub" crashes when presented tagged traffic. (a Cisco 2900XL, for example)
– Ricky Beam
Nov 12 at 19:05
Can you reconfigure things so the unmanaged switch is not in that path? Would be a better network design if so.
– Criggie
Nov 12 at 19:43
Normally it would not be a problem.
– Cown
Nov 12 at 15:53
Normally it would not be a problem.
– Cown
Nov 12 at 15:53
1
1
Possible? Yes. Recommended? No. A "hub" that isn't vlan aware could do anything with tagged traffic. The biggest problem: the frames are now 4 bytes bigger, which can cause them to be dropped as oversized. (1518 vs 1514) In the absolute worst case, your "hub" crashes when presented tagged traffic. (a Cisco 2900XL, for example)
– Ricky Beam
Nov 12 at 19:05
Possible? Yes. Recommended? No. A "hub" that isn't vlan aware could do anything with tagged traffic. The biggest problem: the frames are now 4 bytes bigger, which can cause them to be dropped as oversized. (1518 vs 1514) In the absolute worst case, your "hub" crashes when presented tagged traffic. (a Cisco 2900XL, for example)
– Ricky Beam
Nov 12 at 19:05
Can you reconfigure things so the unmanaged switch is not in that path? Would be a better network design if so.
– Criggie
Nov 12 at 19:43
Can you reconfigure things so the unmanaged switch is not in that path? Would be a better network design if so.
– Criggie
Nov 12 at 19:43
add a comment |
2 Answers
2
active
oldest
votes
up vote
7
down vote
An unmanaged switch will only have one VLAN. Some unmanaged switches will drop tagged frames as damaged, others will strip the tag, and some will simply pass the frames unchanged. Unless you try it, you have no way to know how your switch acts. For the switches that strip the tags, all the frames will be placed into the native (untagged) VLAN as they pass through the switch.
If your VLAN switch is a layer-3 switch, then you are better off using it as the LAN router and creating a routed link to the router, which can act as the WAN router. You will need to either use static routes on the WAN router, or you will need to run a routing protocol between the WAN router and the layer-3 switch as the LAN router.
answered Nov 12 at 15:55
Ron Maupin♦
59.9k1058109
Your VLAN doesn't work like mine. Then again, mine won't allow two VLANs to communicate between switches on the same wire.
– Joshua
Nov 12 at 17:27
@Joshua if that's true, do you really even have vlans? 802.1q, which allows for multiple vlans in the same switch port via tagging, has been a thing for a loooong time now, and it's hard to find a managed switch that won't do this.
– Joel Coehoorn
Nov 12 at 17:28
@JoelCoehoorn: If I can reassign machines to broadcast domains remotely it's a VLAN right?
– Joshua
Nov 12 at 17:30
add a comment |
up vote
0
down vote
Yes, you can do what you're suggesting without any problem.
In practice, the dumb switch treats everything as if it's on vlan1. Technically though, vlan tags are removed when leaving access ports and applied when entering. Vlan tags are only kept in the frame between switches when crossing a trunk port. Since you're not creating a trunk between to the dumb switch (or router), then vlan tagging is not an issue.
answered Nov 12 at 15:59
aletoledo
1884
The router will have the VLAN 10 declared, any problem with your last sentence ?
– Puma
Nov 12 at 16:03
If you're tagging at the router with a sub-interface, then generally you want to have that go into a trunk port on the switch. Since the dumb switch is incapable of forming a trunk, then it might not work as you expect. If you can get the router and the smart switch to both trunk to the dumb switch, then whatever packets that cross the dumb switch will still contain the vlan tags and you'll be good to go. However this is an unusual design and it's better to just put the trunk straight to a proper layer3 switch.
– aletoledo
Nov 12 at 16:15
5
"whatever packets that cross the dumb switch will still contain the vlan tags" That is not a given. The behavior of an unmanaged switch when faced with VLAN tags is undefined, and some unmanaged switches will drop the frames as damaged and some will strip the tags.
– Ron Maupin♦
Nov 12 at 16:44
add a comment |
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
7
down vote
An unmanaged switch will only have one VLAN. Some unmanaged switches will drop tagged frames as damaged, others will strip the tag, and some will simply pass the frames unchanged. Unless you try it, you have no way to know how your switch acts. For the switches that strip the tags, all the frames will be placed into the native (untagged) VLAN as they pass through the switch.
If your VLAN switch is a layer-3 switch, then you are better off using it as the LAN router and creating a routed link to the router, which can act as the WAN router. You will need to either use static routes on the WAN router, or you will need to run a routing protocol between the WAN router and the layer-3 switch as the LAN router.
answered Nov 12 at 15:55
Ron Maupin♦
59.9k1058109
Your VLAN doesn't work like mine. Then again, mine won't allow two VLANs to communicate between switches on the same wire.
– Joshua
Nov 12 at 17:27
@Joshua if that's true, do you really even have vlans? 802.1q, which allows for multiple vlans in the same switch port via tagging, has been a thing for a loooong time now, and it's hard to find a managed switch that won't do this.
– Joel Coehoorn
Nov 12 at 17:28
@JoelCoehoorn: If I can reassign machines to broadcast domains remotely it's a VLAN right?
– Joshua
Nov 12 at 17:30
add a comment |
up vote
7
down vote
An unmanaged switch will only have one VLAN. Some unmanaged switches will drop tagged frames as damaged, others will strip the tag, and some will simply pass the frames unchanged. Unless you try it, you have no way to know how your switch acts. For the switches that strip the tags, all the frames will be placed into the native (untagged) VLAN as they pass through the switch.
If your VLAN switch is a layer-3 switch, then you are better off using it as the LAN router and creating a routed link to the router, which can act as the WAN router. You will need to either use static routes on the WAN router, or you will need to run a routing protocol between the WAN router and the layer-3 switch as the LAN router.
answered Nov 12 at 15:55
Ron Maupin♦
59.9k1058109
Your VLAN doesn't work like mine. Then again, mine won't allow two VLANs to communicate between switches on the same wire.
– Joshua
Nov 12 at 17:27
@Joshua if that's true, do you really even have vlans? 802.1q, which allows for multiple vlans in the same switch port via tagging, has been a thing for a loooong time now, and it's hard to find a managed switch that won't do this.
– Joel Coehoorn
Nov 12 at 17:28
@JoelCoehoorn: If I can reassign machines to broadcast domains remotely it's a VLAN right?
– Joshua
Nov 12 at 17:30
add a comment |
up vote
7
down vote
up vote
7
down vote
An unmanaged switch will only have one VLAN. Some unmanaged switches will drop tagged frames as damaged, others will strip the tag, and some will simply pass the frames unchanged. Unless you try it, you have no way to know how your switch acts. For the switches that strip the tags, all the frames will be placed into the native (untagged) VLAN as they pass through the switch.
If your VLAN switch is a layer-3 switch, then you are better off using it as the LAN router and creating a routed link to the router, which can act as the WAN router. You will need to either use static routes on the WAN router, or you will need to run a routing protocol between the WAN router and the layer-3 switch as the LAN router.
answered Nov 12 at 15:55
Ron Maupin♦
59.9k1058109
An unmanaged switch will only have one VLAN. Some unmanaged switches will drop tagged frames as damaged, others will strip the tag, and some will simply pass the frames unchanged. Unless you try it, you have no way to know how your switch acts. For the switches that strip the tags, all the frames will be placed into the native (untagged) VLAN as they pass through the switch.
If your VLAN switch is a layer-3 switch, then you are better off using it as the LAN router and creating a routed link to the router, which can act as the WAN router. You will need to either use static routes on the WAN router, or you will need to run a routing protocol between the WAN router and the layer-3 switch as the LAN router.
answered Nov 12 at 15:55
Ron Maupin♦
59.9k1058109
edited Nov 12 at 16:14
answered Nov 12 at 15:55
Ron Maupin♦
59.9k1058109
answered Nov 12 at 15:55
Ron Maupin♦
59.9k1058109
answered Nov 12 at 15:55
Ron Maupin♦
59.9k1058109
59.9k1058109
Your VLAN doesn't work like mine. Then again, mine won't allow two VLANs to communicate between switches on the same wire.
– Joshua
Nov 12 at 17:27
@Joshua if that's true, do you really even have vlans? 802.1q, which allows for multiple vlans in the same switch port via tagging, has been a thing for a loooong time now, and it's hard to find a managed switch that won't do this.
– Joel Coehoorn
Nov 12 at 17:28
@JoelCoehoorn: If I can reassign machines to broadcast domains remotely it's a VLAN right?
– Joshua
Nov 12 at 17:30
add a comment |
Your VLAN doesn't work like mine. Then again, mine won't allow two VLANs to communicate between switches on the same wire.
– Joshua
Nov 12 at 17:27
@Joshua if that's true, do you really even have vlans? 802.1q, which allows for multiple vlans in the same switch port via tagging, has been a thing for a loooong time now, and it's hard to find a managed switch that won't do this.
– Joel Coehoorn
Nov 12 at 17:28
@JoelCoehoorn: If I can reassign machines to broadcast domains remotely it's a VLAN right?
– Joshua
Nov 12 at 17:30
Your VLAN doesn't work like mine. Then again, mine won't allow two VLANs to communicate between switches on the same wire.
– Joshua
Nov 12 at 17:27
Your VLAN doesn't work like mine. Then again, mine won't allow two VLANs to communicate between switches on the same wire.
– Joshua
Nov 12 at 17:27
@Joshua if that's true, do you really even have vlans? 802.1q, which allows for multiple vlans in the same switch port via tagging, has been a thing for a loooong time now, and it's hard to find a managed switch that won't do this.
– Joel Coehoorn
Nov 12 at 17:28
@Joshua if that's true, do you really even have vlans? 802.1q, which allows for multiple vlans in the same switch port via tagging, has been a thing for a loooong time now, and it's hard to find a managed switch that won't do this.
– Joel Coehoorn
Nov 12 at 17:28
@JoelCoehoorn: If I can reassign machines to broadcast domains remotely it's a VLAN right?
– Joshua
Nov 12 at 17:30
@JoelCoehoorn: If I can reassign machines to broadcast domains remotely it's a VLAN right?
– Joshua
Nov 12 at 17:30
add a comment |
up vote
0
down vote
Yes, you can do what you're suggesting without any problem.
In practice, the dumb switch treats everything as if it's on vlan1. Technically though, vlan tags are removed when leaving access ports and applied when entering. Vlan tags are only kept in the frame between switches when crossing a trunk port. Since you're not creating a trunk between to the dumb switch (or router), then vlan tagging is not an issue.
answered Nov 12 at 15:59
aletoledo
1884
The router will have the VLAN 10 declared, any problem with your last sentence ?
– Puma
Nov 12 at 16:03
If you're tagging at the router with a sub-interface, then generally you want to have that go into a trunk port on the switch. Since the dumb switch is incapable of forming a trunk, then it might not work as you expect. If you can get the router and the smart switch to both trunk to the dumb switch, then whatever packets that cross the dumb switch will still contain the vlan tags and you'll be good to go. However this is an unusual design and it's better to just put the trunk straight to a proper layer3 switch.
– aletoledo
Nov 12 at 16:15
5
"whatever packets that cross the dumb switch will still contain the vlan tags" That is not a given. The behavior of an unmanaged switch when faced with VLAN tags is undefined, and some unmanaged switches will drop the frames as damaged and some will strip the tags.
– Ron Maupin♦
Nov 12 at 16:44
add a comment |
up vote
0
down vote
Yes, you can do what you're suggesting without any problem.
In practice, the dumb switch treats everything as if it's on vlan1. Technically though, vlan tags are removed when leaving access ports and applied when entering. Vlan tags are only kept in the frame between switches when crossing a trunk port. Since you're not creating a trunk between to the dumb switch (or router), then vlan tagging is not an issue.
answered Nov 12 at 15:59
aletoledo
1884
The router will have the VLAN 10 declared, any problem with your last sentence ?
– Puma
Nov 12 at 16:03
If you're tagging at the router with a sub-interface, then generally you want to have that go into a trunk port on the switch. Since the dumb switch is incapable of forming a trunk, then it might not work as you expect. If you can get the router and the smart switch to both trunk to the dumb switch, then whatever packets that cross the dumb switch will still contain the vlan tags and you'll be good to go. However this is an unusual design and it's better to just put the trunk straight to a proper layer3 switch.
– aletoledo
Nov 12 at 16:15
5
"whatever packets that cross the dumb switch will still contain the vlan tags" That is not a given. The behavior of an unmanaged switch when faced with VLAN tags is undefined, and some unmanaged switches will drop the frames as damaged and some will strip the tags.
– Ron Maupin♦
Nov 12 at 16:44
add a comment |
up vote
0
down vote
up vote
0
down vote
Yes, you can do what you're suggesting without any problem.
In practice, the dumb switch treats everything as if it's on vlan1. Technically though, vlan tags are removed when leaving access ports and applied when entering. Vlan tags are only kept in the frame between switches when crossing a trunk port. Since you're not creating a trunk between to the dumb switch (or router), then vlan tagging is not an issue.
answered Nov 12 at 15:59
aletoledo
1884
Yes, you can do what you're suggesting without any problem.
In practice, the dumb switch treats everything as if it's on vlan1. Technically though, vlan tags are removed when leaving access ports and applied when entering. Vlan tags are only kept in the frame between switches when crossing a trunk port. Since you're not creating a trunk between to the dumb switch (or router), then vlan tagging is not an issue.
answered Nov 12 at 15:59
aletoledo
1884
answered Nov 12 at 15:59
aletoledo
1884
answered Nov 12 at 15:59
aletoledo
1884
answered Nov 12 at 15:59
aletoledo
1884
1884
The router will have the VLAN 10 declared, any problem with your last sentence ?
– Puma
Nov 12 at 16:03
If you're tagging at the router with a sub-interface, then generally you want to have that go into a trunk port on the switch. Since the dumb switch is incapable of forming a trunk, then it might not work as you expect. If you can get the router and the smart switch to both trunk to the dumb switch, then whatever packets that cross the dumb switch will still contain the vlan tags and you'll be good to go. However this is an unusual design and it's better to just put the trunk straight to a proper layer3 switch.
– aletoledo
Nov 12 at 16:15
5
"whatever packets that cross the dumb switch will still contain the vlan tags" That is not a given. The behavior of an unmanaged switch when faced with VLAN tags is undefined, and some unmanaged switches will drop the frames as damaged and some will strip the tags.
– Ron Maupin♦
Nov 12 at 16:44
add a comment |
The router will have the VLAN 10 declared, any problem with your last sentence ?
– Puma
Nov 12 at 16:03
If you're tagging at the router with a sub-interface, then generally you want to have that go into a trunk port on the switch. Since the dumb switch is incapable of forming a trunk, then it might not work as you expect. If you can get the router and the smart switch to both trunk to the dumb switch, then whatever packets that cross the dumb switch will still contain the vlan tags and you'll be good to go. However this is an unusual design and it's better to just put the trunk straight to a proper layer3 switch.
– aletoledo
Nov 12 at 16:15
5
"whatever packets that cross the dumb switch will still contain the vlan tags" That is not a given. The behavior of an unmanaged switch when faced with VLAN tags is undefined, and some unmanaged switches will drop the frames as damaged and some will strip the tags.
– Ron Maupin♦
Nov 12 at 16:44
The router will have the VLAN 10 declared, any problem with your last sentence ?
– Puma
Nov 12 at 16:03
The router will have the VLAN 10 declared, any problem with your last sentence ?
– Puma
Nov 12 at 16:03
If you're tagging at the router with a sub-interface, then generally you want to have that go into a trunk port on the switch. Since the dumb switch is incapable of forming a trunk, then it might not work as you expect. If you can get the router and the smart switch to both trunk to the dumb switch, then whatever packets that cross the dumb switch will still contain the vlan tags and you'll be good to go. However this is an unusual design and it's better to just put the trunk straight to a proper layer3 switch.
– aletoledo
Nov 12 at 16:15
If you're tagging at the router with a sub-interface, then generally you want to have that go into a trunk port on the switch. Since the dumb switch is incapable of forming a trunk, then it might not work as you expect. If you can get the router and the smart switch to both trunk to the dumb switch, then whatever packets that cross the dumb switch will still contain the vlan tags and you'll be good to go. However this is an unusual design and it's better to just put the trunk straight to a proper layer3 switch.
– aletoledo
Nov 12 at 16:15
5
5
"whatever packets that cross the dumb switch will still contain the vlan tags" That is not a given. The behavior of an unmanaged switch when faced with VLAN tags is undefined, and some unmanaged switches will drop the frames as damaged and some will strip the tags.
– Ron Maupin♦
Nov 12 at 16:44
"whatever packets that cross the dumb switch will still contain the vlan tags" That is not a given. The behavior of an unmanaged switch when faced with VLAN tags is undefined, and some unmanaged switches will drop the frames as damaged and some will strip the tags.
– Ron Maupin♦
Nov 12 at 16:44
add a comment |
Puma is a new contributor. Be nice, and check out our Code of Conduct.
Puma is a new contributor. Be nice, and check out our Code of Conduct.
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Normally it would not be a problem.
– Cown
Nov 12 at 15:53
1
Possible? Yes. Recommended? No. A "hub" that isn't vlan aware could do anything with tagged traffic. The biggest problem: the frames are now 4 bytes bigger, which can cause them to be dropped as oversized. (1518 vs 1514) In the absolute worst case, your "hub" crashes when presented tagged traffic. (a Cisco 2900XL, for example)
– Ricky Beam
Nov 12 at 19:05
Can you reconfigure things so the unmanaged switch is not in that path? Would be a better network design if so.
– Criggie
Nov 12 at 19:43