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Thanks
Ignazio

Il Dom 31 Lug 2022, 19:13 Miguel Lavalle <miguel at mlavalle.com> ha scritto:

> You got it!
>
> On Sat, Jul 30, 2022 at 1:51 PM Ignazio Cassano <ignaziocassano at gmail.com>
> wrote:
>
>> Hello, sorry but my networking skill is very poor.
>> Let me do explain what I understood
>> With routed provider network I can use a single provider network to
>> represent multiple l2 networks.
>> For example use case 1:
>> Compute node A on vlan 100.
>> Compute node B on vlan 100.
>> I can create more then one segments on vlan 100 with different cidr.
>> Segment 1 with 192.168.100.0/24.
>> Segment 2 with 192.168.101.0/24
>>
>> Use case case 2:
>>  I can also have nodes on different  vlan and using aggregates to address
>> vm on compute nodes depending on ip address.
>> Compute node A and B on vlan 100.
>> Compute node C and D on vlan 101.
>> Vm on segments belonging to vlan 100 are addressed on Cimpute node A or B.
>> Vm on segments belonging to vlan 101 are addressed on compute node C or D.
>>
>> In both use case phisical router must be configured because openstack
>> virtual router cannot be used.
>> Please, let me know if I undertood well.
>> Ignazio
>>
>> Il Mer 27 Lug 2022, 16:50 Miguel Lavalle <miguel at mlavalle.com> ha
>> scritto:
>>
>>> Ignazio,
>>>
>>> You might find the following two presentations useful to understand what
>>> segments are and how they are used in routed networks:
>>>
>>>
>>> https://www.openstack.org/videos/summits/austin-2016/mapping-real-networks-to-physical-networks-segments-and-logical-networks-in-neutron
>>>
>>> https://www.openstack.org/videos/summits/barcelona-2016/scaling-up-openstack-networking-with-routed-networks
>>>
>>> And to summarize what you will find in those presentations:
>>>
>>> 1) A segment is a single L2 broadcast domain, be it a vlan or a vxlan or
>>> any other way to realize a L2 broadcast domain in the networking fabric.
>>> 2) A Neutron network can be created stitching together 1 or several
>>> segments. If after putting several segments together in a Neutron network
>>> they become a single L2 broadcast domain (i.e. they are stitched together
>>> via switching) then you have a multi-segment Neutron network. However ....
>>> 3) If the segments in a Neutron network are stitched together with L3
>>> routers, then you have a routed provider network. In such networks, each
>>> segment is a separate L2 broadcast domain, which should provide higher
>>> levels of scalability
>>> 4) To better understand the terminology, you may also find it useful to
>>> understand the distinction between  "provider networks" and "tenant
>>> networks". A provider network is one that was mapped explicitly at creation
>>> by a cloud admin to specific segments, most likely to achieve certain
>>> performance / scalability goals. A tenant network is one for which, at
>>> creation, Neutron assigned automatically a segment
>>>
>>> Best regards
>>>
>>> Miguel
>>>
>>> On Wed, Jul 27, 2022 at 3:01 AM Ignazio Cassano <
>>> ignaziocassano at gmail.com> wrote:
>>>
>>>> Hello, thanks for your reply.
>>>> The segment id is the vlan id  (in your example 101) ?
>>>> My understanding is that  some compute nodes in a rack are connected to
>>>> a vlan, and other on another vlan.
>>>> Then I can create a network (segmentation1) and scheduler put the vm on
>>>> the compute node where vlan is present.
>>>> So for users exists only segmentaion1 network and they do not know it
>>>> is splitted in more vlans.
>>>> Is it correct ?
>>>> Ignazio
>>>>
>>>> Il giorno mer 27 lug 2022 alle ore 09:27 Lajos Katona <
>>>> katonalala at gmail.com> ha scritto:
>>>>
>>>>> Hi,
>>>>> I suppose you referenced this document:
>>>>>
>>>>> https://docs.openstack.org/neutron/latest/admin/config-routed-networks.html
>>>>>
>>>>> In Neutron terminology segments appear on different layers, on the API
>>>>> a segment is a network type / seg. id / phys-net / net uuid tuple (see [1]).
>>>>> What is interesting here that this segment has to be a representation
>>>>> on the compute where l2-agent (ovs-agent) can know which segment is the one
>>>>> it can bind ports.
>>>>> That cfg option is in ml2_conf.ini, and bridge_mappings, where the
>>>>> admin/deployer can state which bridge (like br-ex) is connected to which
>>>>> provider network (out of Openstack's control).
>>>>> So for example a sample config in ml_conf.ini like this:
>>>>>
>>>>> bridge_mappings = public:br-ex,physnet1:br0
>>>>>
>>>>> Means that on that compute VM ports can be bound which has a network
>>>>> segment like this: ( network_type: vlan, physical_network: *physnet1*, segmentation_id:
>>>>> 101, network_id: 1234-56..)
>>>>> More computes can have the same bridge-physnet mapping, the deployer's
>>>>> responsibility is to have these connected to the same switch, whatever.
>>>>>
>>>>> [1]:
>>>>> https://docs.openstack.org/api-ref/network/v2/index.html?expanded=create-segment-detail#segments
>>>>>
>>>>> Ignazio Cassano <ignaziocassano at gmail.com> ezt írta (időpont: 2022.
>>>>> júl. 26., K, 21:04):
>>>>>
>>>>>> Hello All, I am reading documentation about routed provider network.
>>>>>> It reports: "
>>>>>> Routed provider networks imply that compute nodes reside on different
>>>>>> segments. "
>>>>>>
>>>>>> What does mean ?
>>>>>> What is a segment it this case ?
>>>>>> Thanks for helping me"
>>>>>> Ignazio
>>>>>>
>>>>>
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