UPLINK Access Port

[Muhammad Kamran Shahzad]

Dear Experts

My Uplink provided gave me Layer2 Access Ports (don't know which vlan is that)

I have my cisco switches
How I can configure multiple vlans and send to upstream on Trunk interface ?
Please advise

Many Thanks

[Richard Burts]

There are things that we do not know about your situation and that makes it difficult to give you good advice. You refer to an Uplink. Is this an ISP or is it something else? You refer to Access Ports. Is this a single port or is it multiple ports? If the Uplink really means Access Port (not just a wire to connect to) then you can not use an access port as a trunk.

An important part of connecting a private network to the Internet is to have Network Address Translation. Is the Uplink going to do NAT for your addresses? Or is the Uplink expecting you to do your own NAT? Most Cisco switches do not support doing NAT. So that may be a problem.

[Muhammad Kamran Shahzad]

Hi Richard
Thanks for your Reply
Basically I have both situations (One Uplink in one city) and second city have 2 uplinks

We will not combine both , so we can discuss separately each 

Our uplink is an ISP and running PPPoE Server behind
They gave us Access Port connectivity and yes they NAT our traffic as from our side we will only dial PPPoE ID's at client end
One port is coming from ISP which is access port and we are currently using Cisco switch on default configuration as all ports are in same PVID so it works but some time if there is broadcast storm then whole traffic disturbed
we want to divide in multiple vlans in our side and send all data to uplink which is access port

Thanks

[Richard Burts]

Thanks for the clarifications. First let us discuss the one uplink. It is good to know that you are connecting to an ISP, that they are running PPPoE, and that they will do address translation for your addresses. Are you using DHCP to assign IP addresses to hosts in the network? Or will the ISP provide the DHCP assignments? As long as you are in a single network things will be fairly straightforward. The ISP connection will be an access port in the vlan you are using (if you are using defaults then this would be vlan 1, but the ISP does not care which vlan). The default gateway for hosts in your network will be the ISP address. If you do divide your network into several vlans (to isolate some broadcast traffic which can be a good thing) then it gets more complicated. I don't know what type of switches you have and whether those switches can support running a trunk over a PPPoE connection - or whether the ISP would support that. The alternative would be to configured your port connecting to the ISP as a routed port (basically makes it into a layer 3 port having its own IP address). You would enable IP routing on your switch, configure multiple vlans, multiple Switched Virtual Interfaces (one per vlan with each having its own subnet with IP addresses). The hosts in each vlan would have their default gateway as the SVI for their vlan. The routing logic for the switch would have a default route with the ISP as the next hop. In this situation the ISP would need to do NAT for multiple networks. Are they willing to do that?

For the city with 2 links it would probably make sense to have that network divided into 2 networks and the same points would apply to each of those networks.

[Muhammad Kamran Shahzad]

Hi Richard
Thanks for providing feedback
ISP is providing us a connection from where we can dial PPPoE ID so everything else managed by ISP as assigning IP Address by their own dhcp server and assigning qos as well and end user is getting ip from isp provided ip from their own dhcp server
I understand if we can route uplink port to layer 3 then we can route layer 3 traffic but in our case we are not assigning ip addresses to end users
Let say if i create vlan 10 and provide ip address 192.168.10.1/30 to this vlan, and interface gi0/1 is access port on vlan 10 , Interface gi0/24 is routed port and we can set default route to uplink (peer ip) so all users connected to vlan10 will be able to dial pppoe and they will get ip from isp dhcp server ?
and in our case we assume 500 peoples will be connected to vlan 10 so basically we don't need to assign ip to these customers from vlan 10 right ?

Thanks

[Richard Burts]

Thanks for additional information. What I think I understand is that the ISP is providing a connection for PPPoE to your switch, the ISP is using DHCP to provide an IP address for the PPPoE port and DHCP to allow 500 users to get IP addresses and to get access to Internet (including NAT for the 500 host addresses). Is that correct?

I am not clear about your question about vlan 10. Is this in addition to the ISP/DHCP/NAT vlan or is this in place of the 500 address service provided by ISP? In this suggestion would there be 2 outbound links? If so where would the second connection go?

[Muhammad Kamran Shahzad]

Hi Richard
For Clarification I am attaching Network Diagram
There are 2 PPPoE Servers running behind but I am connected with PPPoE Server 1 only
As per attached Diagram ISP gave me access port on vlan 10
I want to create multiple vlans in my switch and send all traffic to uplink as untagged

Please advise Thanks

[Richard Burts]

Thank you for the drawing. It does help clarify the environment. What I think I am seeing is that the ISP environment has many services and is using many vlans with trunking between their switches. They offer you a connection on an access port in vlan 10. This means that traffic on this link would be untagged. This would support your using one vlan. Technically you could use any vlan number you want on your switch. But it would seem to make sense to use vlan 10. Without negotiating with the ISP for a different type of connection I do not see how you could use multiple vlans in your switch. Certainly you can not send traffic from multiple vlans over the existing link with no vlan tags.

[MHM Cisco World]

QinQ is solution here I think