inbound/outbound traffic cross router

[eigrpy]

Hi Here is a concept that I hope you help to clear. Please correct where it is wrong below. Thank you in advance
In a company network, its edge routerA is connected to ISP' routerB. Behind routerA there are a userA and a web serverA. In public internet, there are a userB and web serverB. If the userA visit web serverB, we consider the traffic as inbound traffic because the data flow or traffic goes inbound from serverB to userA. If the userB visit web serverA, we call the traffic as outbound traffic because the data flow or traffic goes outbound from serverA to userB

[Carlos Villagran]

Hi!

I think this could be one of the most confusing concepts in networking. This is all about perspective of the nodes where traffic is crossing. 

If user on network A communicates with web server on B the packet will traverse to the gateway router A and the local interface will perceive this communication as INBOUND, when the packet leaves the router to the internet through the ISP facing interface that same router will perceive that as OUTBOUND. When the packet arrives to router B's  ISP facing interface this will be perceived as INBOUND, the packet finally will be forwarded to the web server B through the Local interface and it will be perceived as OUTBOUND. 

Lastly, the Web server on B will have to respond to that message it received and then the communication will be the exact opposite as the stated above.

Hope it's kind of clear and helpful! 

Best regards.

JC

[eigrpy]

Thank you so much for your reply. 

inbound/outbound is not only one that confusing during the process. it includes some terms, such as routes, packet, data flow, and traffic etc. The packet you mentioned above should be routes, right? 

In order to make it clear, I draw a picture. lets just talk about inside userA who wants to visit an outside web site, serverB: 

In the example(please see picture), userA visits serverB, which means the userA gets data from the serverB. so the data goes from serverB, routerB(ISP), and then to routerA and userA. finally userA gets web message.

From routerA perceptive,  the data flow is inbound from routerB to routerA, and the same data flow is outbound from routerA to userA. From routerB perspective, vice versa

Do you agree? 

[Carlos Villagran]

Exactly, I agree and you are absolutely right, the data flow is INBOUND from router B to router A and OUTBOUND from router A to user A!

Best regards!

JC

[eigrpy]

Another that is confusing me is that routes flow/packet flow are opposite direction with data flow in the case. In the above example, from routerA perspective and for userA to be able to visit serverB, the routes needed to be sent out from routerA to routerB. and the routes is called outbound routes. Can we call the outbound routes as outbound traffic? Thank you

[Carlos Villagran]

Definetely, routes are merely advertisements of router A to router B, these advertisements are of course outbound traffic. Routes are indeed outbound traffic and reflects where your outbound traffic should go.

BR!

JC

[eigrpy]

There are several terms that I still feel confusing. Routes flow is opposite direction of data flow, right? I see some people consider data flow as traffic, and other consider routes flow as traffic. so, I think that the term traffic could stand for data flow or routes flow, Ether one is Ok, do you think so?

Thank you again