Port-channel+eBGP Load Balance traffic problem

[Baratheon]

My company's data center is currently using a Cisco C9500-24Y4C connected to an ISP router x670 extreme.
We've configured a port-channel with 4x 10G ports, divided into two VLANs (VLAN2 and VLAN3).
Our BGP configurations are identical on both sides, and we've confirmed that the connection is established.
However, we've encountered an issue where it seems like traffic is only utilizing one of the four interfaces in the port-channel,
and we're not achieving the desired load balancing. Can you please advise on what steps or configurations may be missing?

Thanks in advance,I will appreciate your help.

[MHM Cisco World]

the load balance start from L3 then down to L1 (port channel)
L3 we can control the load 
L1 we can not 

for L3
here I ask you the config of BGP!
the eBGP usually select and use one path, to use multipath you need to change the config.

Thanks A Lot
MHM

[Baratheon]

According to your explanation, are you suggesting that eBGP can only control load balancing in L3 scenarios? Is this understanding correct? I hope this is not the only solution..I genuinely appreciate your guidance. Thank you.

[Torbjørn]

If the links in the etherchannel is bundled correctly, which I would guess they based on the configuration provided - this is not a layer 3/BGP issue. Can you post the output of show etherchannel summary to verify?

Which etherchannel load-balancing settings you should choose is highly dependent on the traffic that traverses the etherchannel. Assuming the VLANs are only used for the link network there will be very few MAC addresses in use, you should hence load-balance based on layer3 and/or layer 4 information. If most traffic being sent from the 9500 is NATed behind one address you should avoid using source IP for the load-balancing hashing. You should try to include as many parameters that will vary for the different flows traversing the link. My guess based on the information you have provided(and assuming source-NAT is in use) would be that you will get the best results selecting one of these:

dst-ip               Dst IP Addr
dst-mixed-ip-port    Dst IP Addr and TCP/UDP Port
src-dst-port         Src XOR Dst TCP/UDP Port

If possible your ISP should also configure their end with similar(but opposite) load-balancing settings. Keep in mind that the load-balancing configured only applies to traffic being sent out of the interface.

[Baratheon]

@Torbjørn 

Thank you for your response. Please allow me to continue the discussion with you.

#show etherchannel summary
Flags: D - down P - bundled in port-channel
I - stand-alone s - suspended
H - Hot-standby (LACP only)
R - Layer3 S - Layer2
U - in use f - failed to allocate aggregator

M - not in use, minimum links not met
u - unsuitable for bundling
w - waiting to be aggregated
d - default port

A - formed by Auto LAG

Number of channel-groups in use: 4
Number of aggregators: 4

Group       Port-channel         Protocol        Ports
------+-------------+-----------+-----------------------------------------------
1               Po1(SU)              LACP         Twe1/0/1(P) Twe1/0/2(P)
                                                             Twe1/0/3(P) Twe1/0/4(P)

I will attempt to use the (config)#port-channel load-balance src-dst-mixed-ip-port configuration,which signifies load balancing for uploads. However,I have another question to inquire.
According to your description, does ISP (X670) also need corresponding configurations? What would be the corresponding configuration for X670?

[Torbjørn · Accepted solution]

@Baratheon , that is correct. Each device can only control which link to forward the frames onto. The X670 would also require a change to it`s etherchannel load-balancing as the default seems to be source+destination MAC addresses. Exos configuration is unfortunately not something I am familiar with. Your ISP can likely assist you with the X670 configuration if you describe that you wish to load-balance the etherchannel based on source and destination port numbers. This article describes exos etherchannel configuration and load-balancing options: https://extreme-networks.my.site.com/ExtrArticleDetail?n=000002358.

Your command output confirms that your etherchannel is bundled as it should and that this is an etherchannel load-balancing issue.

[Baratheon]

@Torbjørn Thank you for the substantial assistance and valuable tips I received through our discussions. I successfully achieved the ultimate outcome of load balancing. Thank you.

[MHM Cisco World]

sorry can you more elaborate, I can not get your Q?

Thanks A Lot
MHM 

[MHM Cisco World]

I check your config'

It is as I mention before two path and ebgp select only one best path and inkect it to RIB.

You can use ebgp multipath

Or 

You can use loopback as update source of bgp' and config two static route to reach this loopback.

Thanks A Lot
MHM

[Baratheon]

OK!! I will try the valuable suggestions you provided. Thank you!