a VLAN maps several subnet?
i've read this post: Multiple Subnets in a VLAN
and am wondering about the possible conflicts when using several subnets in a VLAN.
the recommended design is of course put a IP subnet in a vlan.
if i configure several ip subnets in a vlan, e.g. some hosts in 10.1.1.0/24, some hosts in 10.2.2.0/24 and both under a vlan, will these two networks interrupt each other? if there's actually no impact then why is such design not prefered?
vlan subnet
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i've read this post: Multiple Subnets in a VLAN
and am wondering about the possible conflicts when using several subnets in a VLAN.
the recommended design is of course put a IP subnet in a vlan.
if i configure several ip subnets in a vlan, e.g. some hosts in 10.1.1.0/24, some hosts in 10.2.2.0/24 and both under a vlan, will these two networks interrupt each other? if there's actually no impact then why is such design not prefered?
vlan subnet
asked 2 hours ago
user53815
212
New contributor
user53815 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
i've read this post: Multiple Subnets in a VLAN
and am wondering about the possible conflicts when using several subnets in a VLAN.
the recommended design is of course put a IP subnet in a vlan.
if i configure several ip subnets in a vlan, e.g. some hosts in 10.1.1.0/24, some hosts in 10.2.2.0/24 and both under a vlan, will these two networks interrupt each other? if there's actually no impact then why is such design not prefered?
vlan subnet
asked 2 hours ago
user53815
212
New contributor
user53815 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
i've read this post: Multiple Subnets in a VLAN
and am wondering about the possible conflicts when using several subnets in a VLAN.
the recommended design is of course put a IP subnet in a vlan.
if i configure several ip subnets in a vlan, e.g. some hosts in 10.1.1.0/24, some hosts in 10.2.2.0/24 and both under a vlan, will these two networks interrupt each other? if there's actually no impact then why is such design not prefered?
vlan subnet
vlan subnet
asked 2 hours ago
user53815
212
New contributor
user53815 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 hours ago
user53815
212
New contributor
user53815 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 hours ago
user53815
212
New contributor
user53815 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 2 hours ago
user53815
212
asked 2 hours ago
user53815
212
212
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user53815 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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user53815 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.
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1 Answer
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This is possible however:
- you still need a router to have the hosts from one subnet to communicate with the hosts in the other subnet
- in a modern switched environment there's no collision, so this is not a issue, but you still have broadcast. All hosts will see the broadcasts from both domains which take some part of the bandwidth.
- Access Control Lists are bounded to interfaces. So to use ACL to limit traffic between the subnets you are limited to a single interface to place ingress / outgress rules; this is stil doable but more limited
- any host can potentially hear some traffic pertaining to the other subnet. That's a security issue.
- when troubleshooting a network issue, you may have to sniff traffic (with utility like tcpdump or wireshark), having several IP networks mixed render this or other troubleshooting more difficult
- overall, this is more complex to maintain and less scalable than having one subnet per vlan.
Basically there's rarely a benefit in doing so, even if you can encounter some corner case where it is the simplest solution (or a temporary dirty fix, but in IT, a temporary setup often last years....).
answered 1 hour ago
JFL
10.5k11235
Although you're generally correct, there are some borderline cases where multiple IP subnets in the same VLAN may be beneficial. I've successfully used it for a finer control on SA/DA load distribution on a LAG trunk (for backup). It's also sometimes used when migrating or renumbering subnets as a stopgap.
– Zac67
14 mins ago
@Zac67 agree. I indeed had to use this a few times myself but always feel ashamed in doing so ;) I felt it was borderline enough to leave it out but I'll edit in this sense.
– JFL
8 mins ago
add a comment |
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This is possible however:
- you still need a router to have the hosts from one subnet to communicate with the hosts in the other subnet
- in a modern switched environment there's no collision, so this is not a issue, but you still have broadcast. All hosts will see the broadcasts from both domains which take some part of the bandwidth.
- Access Control Lists are bounded to interfaces. So to use ACL to limit traffic between the subnets you are limited to a single interface to place ingress / outgress rules; this is stil doable but more limited
- any host can potentially hear some traffic pertaining to the other subnet. That's a security issue.
- when troubleshooting a network issue, you may have to sniff traffic (with utility like tcpdump or wireshark), having several IP networks mixed render this or other troubleshooting more difficult
- overall, this is more complex to maintain and less scalable than having one subnet per vlan.
Basically there's rarely a benefit in doing so, even if you can encounter some corner case where it is the simplest solution (or a temporary dirty fix, but in IT, a temporary setup often last years....).
answered 1 hour ago
JFL
10.5k11235
Although you're generally correct, there are some borderline cases where multiple IP subnets in the same VLAN may be beneficial. I've successfully used it for a finer control on SA/DA load distribution on a LAG trunk (for backup). It's also sometimes used when migrating or renumbering subnets as a stopgap.
– Zac67
14 mins ago
@Zac67 agree. I indeed had to use this a few times myself but always feel ashamed in doing so ;) I felt it was borderline enough to leave it out but I'll edit in this sense.
– JFL
8 mins ago
add a comment |
This is possible however:
- you still need a router to have the hosts from one subnet to communicate with the hosts in the other subnet
- in a modern switched environment there's no collision, so this is not a issue, but you still have broadcast. All hosts will see the broadcasts from both domains which take some part of the bandwidth.
- Access Control Lists are bounded to interfaces. So to use ACL to limit traffic between the subnets you are limited to a single interface to place ingress / outgress rules; this is stil doable but more limited
- any host can potentially hear some traffic pertaining to the other subnet. That's a security issue.
- when troubleshooting a network issue, you may have to sniff traffic (with utility like tcpdump or wireshark), having several IP networks mixed render this or other troubleshooting more difficult
- overall, this is more complex to maintain and less scalable than having one subnet per vlan.
Basically there's rarely a benefit in doing so, even if you can encounter some corner case where it is the simplest solution (or a temporary dirty fix, but in IT, a temporary setup often last years....).
answered 1 hour ago
JFL
10.5k11235
Although you're generally correct, there are some borderline cases where multiple IP subnets in the same VLAN may be beneficial. I've successfully used it for a finer control on SA/DA load distribution on a LAG trunk (for backup). It's also sometimes used when migrating or renumbering subnets as a stopgap.
– Zac67
14 mins ago
@Zac67 agree. I indeed had to use this a few times myself but always feel ashamed in doing so ;) I felt it was borderline enough to leave it out but I'll edit in this sense.
– JFL
8 mins ago
add a comment |
This is possible however:
- you still need a router to have the hosts from one subnet to communicate with the hosts in the other subnet
- in a modern switched environment there's no collision, so this is not a issue, but you still have broadcast. All hosts will see the broadcasts from both domains which take some part of the bandwidth.
- Access Control Lists are bounded to interfaces. So to use ACL to limit traffic between the subnets you are limited to a single interface to place ingress / outgress rules; this is stil doable but more limited
- any host can potentially hear some traffic pertaining to the other subnet. That's a security issue.
- when troubleshooting a network issue, you may have to sniff traffic (with utility like tcpdump or wireshark), having several IP networks mixed render this or other troubleshooting more difficult
- overall, this is more complex to maintain and less scalable than having one subnet per vlan.
Basically there's rarely a benefit in doing so, even if you can encounter some corner case where it is the simplest solution (or a temporary dirty fix, but in IT, a temporary setup often last years....).
answered 1 hour ago
JFL
10.5k11235
This is possible however:
- you still need a router to have the hosts from one subnet to communicate with the hosts in the other subnet
- in a modern switched environment there's no collision, so this is not a issue, but you still have broadcast. All hosts will see the broadcasts from both domains which take some part of the bandwidth.
- Access Control Lists are bounded to interfaces. So to use ACL to limit traffic between the subnets you are limited to a single interface to place ingress / outgress rules; this is stil doable but more limited
- any host can potentially hear some traffic pertaining to the other subnet. That's a security issue.
- when troubleshooting a network issue, you may have to sniff traffic (with utility like tcpdump or wireshark), having several IP networks mixed render this or other troubleshooting more difficult
- overall, this is more complex to maintain and less scalable than having one subnet per vlan.
Basically there's rarely a benefit in doing so, even if you can encounter some corner case where it is the simplest solution (or a temporary dirty fix, but in IT, a temporary setup often last years....).
answered 1 hour ago
JFL
10.5k11235
edited 6 mins ago
answered 1 hour ago
JFL
10.5k11235
answered 1 hour ago
JFL
10.5k11235
answered 1 hour ago
JFL
10.5k11235
10.5k11235
Although you're generally correct, there are some borderline cases where multiple IP subnets in the same VLAN may be beneficial. I've successfully used it for a finer control on SA/DA load distribution on a LAG trunk (for backup). It's also sometimes used when migrating or renumbering subnets as a stopgap.
– Zac67
14 mins ago
@Zac67 agree. I indeed had to use this a few times myself but always feel ashamed in doing so ;) I felt it was borderline enough to leave it out but I'll edit in this sense.
– JFL
8 mins ago
add a comment |
Although you're generally correct, there are some borderline cases where multiple IP subnets in the same VLAN may be beneficial. I've successfully used it for a finer control on SA/DA load distribution on a LAG trunk (for backup). It's also sometimes used when migrating or renumbering subnets as a stopgap.
– Zac67
14 mins ago
@Zac67 agree. I indeed had to use this a few times myself but always feel ashamed in doing so ;) I felt it was borderline enough to leave it out but I'll edit in this sense.
– JFL
8 mins ago
Although you're generally correct, there are some borderline cases where multiple IP subnets in the same VLAN may be beneficial. I've successfully used it for a finer control on SA/DA load distribution on a LAG trunk (for backup). It's also sometimes used when migrating or renumbering subnets as a stopgap.
– Zac67
14 mins ago
Although you're generally correct, there are some borderline cases where multiple IP subnets in the same VLAN may be beneficial. I've successfully used it for a finer control on SA/DA load distribution on a LAG trunk (for backup). It's also sometimes used when migrating or renumbering subnets as a stopgap.
– Zac67
14 mins ago
@Zac67 agree. I indeed had to use this a few times myself but always feel ashamed in doing so ;) I felt it was borderline enough to leave it out but I'll edit in this sense.
– JFL
8 mins ago
@Zac67 agree. I indeed had to use this a few times myself but always feel ashamed in doing so ;) I felt it was borderline enough to leave it out but I'll edit in this sense.
– JFL
8 mins ago
add a comment |
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