Update IOS

[Mlex1]

it's possible update ios from router to router cisco.
scheme for clear understanding, from R3 send ios to R4

[Joseph W. Doherty]

Historically, yes.  I often commonly did that.  I.e. if I had like routers at a branch location, I would update one across the WAN and others, at that branch, from it.

Understand this was decades ago when a WAN link might only be 64 to 256 Kbps.

On current equipment, it likely is still possible, but as link bandwidths continued to increase, there wasn't much need to continue this practice.

[M02@rt37]

Hello @Mlex1 

Possible yes.

It is much better to use a centralized server for uploading and managing ios binaries rather than transferring images router-to-router...

Privilege scp transfer.

[Mlex1]

server has but server also far from router

[Joseph W. Doherty]

If the "distance" causes significant latency but you have decent bandwidth, often a router's default TCP RWIN is too small for the BDP (bandwidth delay product).  Increasing the router's RWIN may increase transfer rate (although writing to flash is comparetively slow).

[Mlex1]

i mean which kind of settings i should do on the router 

[Joseph W. Doherty]

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@Mlex1 wrote:

i mean which kind of settings i should do on the router 

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Are you asking about TCP options?

If so, something like https://www.cisco.com/c/en/us/td/docs/routers/ios/config/17-x/ip-addressing/b-ip-addressing/m_iap-tcp_for_xe.html provides much information.

Of the options, ip tcp window-size is important.  64KB is usually a good value.

ip tcp path-mtu-discovery is another good option to enable, but most important on sender.

ip tcp selective-ack could be of possible benefit.

Pretty much, all else, you can ignore.

BTW, again, the above is for TCP, and anything using it, like FTP, SCP, RCP, etc.  TFTP, though, does not use TCP and generally is very slow across a WAN link with distance based latency.

Also, BTW, understand, the whole point of doing router to router copying is to avoid a slow transfer multiple times.  Often current gen WAN links, with the above options, will support a transfer across a WAN as fast as a local LAN transfer (again, writing to flash, is often then the bottleneck).  So, if WAN and LAN transfers (to flash) take the same time, no need to bother with router to router IOS copies.

[balaji.bandi · Accepted solution]

Not sure which router model (as tagged: ASR1000, IOS XE?)

Router to Router, you can use the guide below:

https://www.cisco.com/c/en/us/support/docs/routers/2500-series-routers/15092-copyimage.html#:~:text=The%20copy%20command%20shown%20next,confirm%5D%20Erasing%20device...

In IOS XE and install mode, all the files will be package files, but you can copy the bin file.

If you have access to the router, you can also run TFTP and copy the files and it will be easy and faster (if this works for you)

[johnlloyd_13]

hi,

yes, you can configure the router as a temporary TFTP server.

i'd suggest do the file transfer during non peak hour so there's no WAN BW congestion. 

see helpful link for the setup that i did:

https://wannabelab.blogspot.com/2014/04/using-cisco-router-as-tftp-server.html

[Joseph W. Doherty]

BTW. . .

yes, you can configure the router as a temporary TFTP server.

TFTP usually offers slow transfer performance if there's much latency, such as often found doing transfers across a WAN.

In the past, across WANs, between routers, I would use RCP, which uses TCP.

i'd suggest do the file transfer during non peak hour so there's no WAN BW congestion.

Or use QoS, so such a transfer only uses otherwise unused bandwidth.

(Laugh, like many others I've conducted maintenance during non-peak usage hours, but, if possible, I like to work during normal business hours.)