Migrate from bloXroute shreds to shredstream.sh

Replace the SDK boundary

The main bloXroute migration happens inside the receiver. The old path enters through a vendor client connected to a proprietary relay network. The new path arrives as ordinary UDP from one known source. Keep the decoder and business logic where their input contracts permit it, but replace the SDK callbacks, session lifecycle, and vendor-specific packet wrapper at ingress.

Draw the current call chain before editing it:

bloXroute relay -> client SDK -> callback adapter -> shred decoder -> filters -> application

The target removes two vendor-owned stages:

203.23.178.228 -> UDP socket -> small intake adapter -> shred decoder -> filters -> application

Inspect what the callback currently hands to the decoder. If it is exactly a raw Solana shred payload, the adapter can stay thin. If it includes provider metadata or framing, list every field your code reads. Preserve application-required metadata such as a local receive timestamp, but do not fabricate vendor fields on the new path.

Keep the bloXroute client installed during the shadow period. A compile-time interface shared by both adapters lets the rest of the process remain stable. The interface should carry payload bytes, ingress source, and monotonic arrival time. It should not expose reconnect or subscription concepts that make no sense for a plain datagram socket.

Specify the socket contract

Write the replacement boundary as testable facts. The transport is UDP. Delivery originates in Frankfurt. Accept datagrams solely from 203.23.178.228. Message length stops at 1228 bytes. Arrival order is unspecified, missing messages are never resent, and the upstream sender cannot be slowed by your queues.

One purchase directs traffic to an ip:port throughout 30 days. Its price is $100, settled in USDC or SOL. Choose the public address and port before building configuration around them.

Represent only the values your receiver needs:

SHRED_BIND_ADDRESS=0.0.0.0SHRED_BIND_PORT=9001SHRED_EXPECTED_SOURCE=203.23.178.228SHRED_MAX_DATAGRAM_BYTES=1228SHRED_ORIGIN=Frankfurt

Binding on all interfaces is an example, not a universal recommendation. Use a specific local address where routing permits it. The public destination can also map through NAT to a different internal address and port, so record both sides.

Open the firewall narrowly

Permit only the purchased UDP port from the published sender. The following iptables example assumes port 9001 and an existing INPUT policy. Review rule order before applying it:

sudo iptables -A INPUT -p udp -s 203.23.178.228 --dport 9001 -j ACCEPT

For a host already managed with nftables, add the equivalent rule to the correct existing table and chain. One typical command is:

sudo nft add rule inet filter input ip saddr 203.23.178.228 udp dport 9001 accept

Use the firewall system your host already owns. Do not install both examples. If a cloud security group or edge firewall sits ahead of the machine, mirror the same source, protocol, and port restriction there.

Check the effective path without trusting configuration output alone:

sudo tcpdump -ni any 'udp and src host 203.23.178.228 and dst port 9001'

Keep the bloXroute port unchanged for now. Separate ingress rules allow both implementations to operate simultaneously and keep every capture attributable.

Capture the verification token

shredstream.sh verifies control before normal forwarding. Start a temporary listener on the actual destination machine, using the exact public mapping selected for service. With netcat, a common diagnostic is:

nc -u -l 9001

Netcat flags differ between operating systems, so confirm the local help output. You can also use socat when available:

socat -v UDP-RECVFROM:9001,reuseaddr,fork -

The preflight payload contains SHREDCAST-VERIFY before its token. Extract that value locally, then return it through the verification flow. Stop the temporary listener before starting your application so both processes do not contend for the port.

Receiving this message proves destination control and network reachability. It does not demonstrate that the old SDK replacement can parse, buffer, or decode the production stream. Continue with the application socket test.

Build a minimal receiver

First make packet ownership visible. This Python example is a diagnostic intake scaffold. Use your production receiver and Solana decoder for live traffic:

import socketimport time EXPECTED_SOURCE = "203.23.178.228"MAX_DATAGRAM = 1228PORT = 9001 sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)sock.bind(("0.0.0.0", PORT)) while True:    payload, peer = sock.recvfrom(2048)    received_ns = time.monotonic_ns()    source_ip, source_port = peer     if source_ip != EXPECTED_SOURCE:        print("unexpected_sender", source_ip, source_port)        continue    if len(payload) > MAX_DATAGRAM:        print("oversize_datagram", len(payload))        continue     print("accepted", received_ns, len(payload))    # Pass the complete payload and timestamp to your shred decoder here.

The 2,048-byte receive allocation is intentionally larger than the allowed payload, so the process can detect and reject an oversize datagram without truncating it first. The product ceiling remains 1228 bytes. In production, count rejects rather than printing every packet.

Adapt this boundary to the language and runtime already used by the bloXroute client integration. Keep one blocking reader or an event-loop socket dedicated to intake, then hand complete messages to a bounded queue. Never concatenate UDP messages or split one across decoder calls.

Make startup fail loudly when the port cannot bind. Emit the chosen bind address, port, expected sender, and maximum size once. A process that silently falls back to another port will pass an uptime check while receiving nothing.

Tune Linux for bursty UDP

Inspect receive-buffer limits before changing them:

sysctl net.core.rmem_default net.core.rmem_maxss -u -a -n -m | grep ':9001'

A local tuning example is:

sudo sysctl -w net.core.rmem_max=16777216

Choose the actual value from measurement and host policy. A larger kernel buffer absorbs short scheduling pauses, but it cannot repair an indefinitely slow decoder. The application should request an appropriate SO_RCVBUF value and then inspect the effective size because Linux may adjust it.

Monitor kernel receive errors, socket drops, queue occupancy, and the oldest queued item. Depth alone can look safe while work becomes too old for the strategy. Put a finite bound between socket intake and decode, then decide whether overflow drops newest or oldest work according to local application needs.

There is no backpressure signal to shredstream.sh. CPU saturation, garbage collection, blocking logs, or a slow downstream call will not reduce send rate. Keep those operations outside the socket reader.

Decode without arrival assumptions

The vendor SDK may have hidden transport details behind a callback. A direct socket exposes them. UDP can deliver later packets before earlier packets, deliver duplicates, or omit a datagram entirely. The new adapter must never equate callback order with Solana shred order.

Pass each accepted payload to the existing decoder as one discrete message. Let protocol identifiers determine its placement. If the decoder previously received an SDK object rather than bytes, write an adapter test using captured examples and confirm every consumed field has a valid new source.

Lost data is not replayed by the sender. A receiver restart only resumes future traffic. Remove retry loops that merely reopen a logical vendor subscription; retain process supervision that rebinds the local socket after a crash. Health should be based on fresh accepted packets and advancing decode work.

Filtering remains downstream of decode. A raw shred does not arrive with a ready-made account, program, or instruction selection supplied by shredstream.sh. Preserve current business filters after reconstruction and compare their shadow results before promotion.

Make duplicate handling idempotent at the application boundary. Two observations of the same protocol item can help measurement, but they must not create two orders or state mutations. Source-aware counters should run before deduplication, while side effects must run afterward.

Shadow the relay-backed path

When possible, run both the bloXroute SDK adapter and plain UDP adapter on one production machine. Timestamp at each ingress before work enters shared queues. This arrangement minimizes clock and hardware differences in the comparison.

Match packet identities and examine three results separately: arrival timing among matched items, coverage unique to either source, and decoded business output. Do not award a latency win to an item absent from the other side. Do not declare application equivalence from packet totals alone.

Exercise receiver failure cases during shadow mode. Restart the new process, fill its queue in a controlled test, present a datagram from an unexpected source, and confirm an oversized message is rejected without damaging the loop. Verify that a malformed payload increments a decoder-specific counter.

The old BDN and SDK remain authoritative until written acceptance criteria pass. Those criteria should cover the Frankfurt route, local drops, queue age, decode errors, coverage, and shadow action agreement. Set the numeric limits from the needs of your system.

Keep vendor-specific and direct-socket metrics in separate namespaces. A generic received counter can hide which path went silent and makes rollback diagnosis needlessly slow.

Promote the plain socket

Cut over after decoding with one authority switch that controls which normalized events may affect production. This keeps network plumbing separate from business authority. The bloXroute lane can remain connected briefly as a comparison and rollback source.

Watch the new path continuously through promotion. Required signals include last accepted packet time, source mismatches, datagram sizes, socket drops, queue age, parse outcomes, decoded progress, and application-side effects. Alert when movement stops even if the process itself remains alive.

If the candidate violates the prewritten boundary, restore the SDK-derived event lane and retain the failure capture. Investigate whether the cause is routing, firewall state, local buffers, adapter behavior, decoder compatibility, or capacity. A quick selector rollback should not require reinstalling the former client.

Once the observation window ends, stop bloXroute packet intake. Confirm that no other product function depends on the same SDK process before removing it. A dedicated shred client can go; a shared client needs a narrower cleanup.

Renew the destination every 30 days when continued service is intended. Assign the USDC or SOL payment and the nominated ip:port to an operational owner.

Remove client baggage

Delete SDK packages, credentials, callback adapters, reconnect state, and relay-specific dashboards only after rollback is closed. Search the codebase and deployment manifests for the vendor client name, but review each occurrence before removal. Some references may describe retained services or historical telemetry.

Close the former inbound port and remove its firewall rule. On the verified port, retain a narrow UDP rule naming 203.23.178.228. Update architecture diagrams to show direct forwarding from Frankfurt into the customer-owned socket.

The final runbook should include the bind configuration, packet capture command, firewall owner, verification procedure, receiver start and stop commands, decoder release, promotion control, metrics, and renewal date. State clearly that your team owns the receiver and decoder.

The finished path is smaller than the SDK integration it replaces. There is no relay client lifecycle inside the application. There is a socket, a strict sender rule, complete datagrams, and the decoder you control. With disorder, loss, and overload handled explicitly, removing the vendor SDK becomes a contained receiver change rather than a rewrite of the trading stack.